**Complete The Maths Equation - 31 July**

Replace the ? by the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

**For Solution :**Click Here

This Blog is a collection of brain teasers, puzzles (maths,fun,brain etc), riddles,Questions, Quiz.

Replace the ? by the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

I drive at an average speed of 30 miles per hour to the railroad station each morning and just catch my train. On a particular morning there was a lot of traffic and at the halfway point I found I had averaged only 15 miles per hour. How fast must I drive for the rest of the way to catch my train?

Difficulty ★★★★☆ Popularity ★★★★★

Outside a room there are three light switches. One of switch is connected to a light bulb inside the room.

Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb ??

Answer & Explanation

Set the first switches on for abt 10min, and then switch on the second switch and then enter the room.

Three cases are possible

1.Bulb is on => second switch is the ans

2.Bulb is off and on touching bulb , you will find bulb to be warm

=>1st switch is the ans.

3.Bulb is off and on touching second bulb , you will find bulb to be normal(not warm)

=>3rd bulb is the ans.

Difficulty ★★★☆☆ Popularity ★★★★☆

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.

How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly

Answer & Explanation

It is not possible to guess only three fruits correctly: the fourth fruit is then correct too! So nobody has guessed three fruits correctly and 123-43-39-31 = 10 people have guessed four fruits correctly.

Difficulty ★★★★★ Popularity ★★★★☆

A man hijacks an aeroplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?

Answer & Explanation

If the officials thought he was jumping with a hostage, they would never risk giving him a faulty parachute.

Difficulty ★★★★☆ Popularity ★★★★★

Alexander is stranded on an island covered in forest.

One day, when the wind is blowing from the west, lightning strikes the west end of the island and sets fire to the forest. The fire is very violent, burning everything in its path, and without intervention the fire will burn the whole island, killing the man in the process.

There are cliffs around the island, so he cannot jump off.

How can the Alexander survive the fire? (There are no buckets or any other means to put out the fire)

Answer & Explanation

Alexander picks up a piece of wood and lights it from the fire on the west end of the island.

He then quickly carries it near the east end of he island and starts a new fire. The wind will cause that fire to burn out the eastern end and he can then shelter in the burnt area.

Alexander survives the fire, but dies of starvation, with all the food in the forest burnt....lolzzz

Difficulty ★★★☆☆ Popularity ★★★★☆

A worker is to perform work for you for seven straight days. In return for his work, you will pay him 1/7th of a bar of gold per day. The worker requires a daily payment of 1/7th of the bar of gold. What and where are the fewest number of cuts to the bar of gold that will allow you to pay him 1/7th each day?

Answer & Explanation

Just 2

Day One: You make your first cut at the 1/7th mark and give that to the worker.

Day Two: You cut 2/7ths and pay that to the worker and receive the original 1/7th in change.

Day three: You give the worker the 1/7th you received as change on the previous day.

Day four: You give the worker 4/7ths and he returns his 1/7th cut and his 2/7th cut as change.

Day Five: You give the worker back the 1/7th cut of gold.

Day Six: You give the worker the 2/7th cut and receive the 1/7th cut back in change.

Day Seven: You pay the worker his final 1/7th.

Difficulty ★★★☆☆ Popularity ★★★★☆

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

Answer & Explanation

The answer is 2. First, divide the coins into 3 equal piles. Place a pile on each side of the scale, leaving the remaining pile of 3 coins off the scale. If the scale does not tip, you know that the 6 coins on the scale are legitimate, and the counterfeit is in the pile in front of you. If the scale does tip, you know the counterfeit is in the pile on the side of the scale that raised up. Either way, put the 6 legitimate coins aside. Having only 3 coins left, put a coin on each side of the scale, leaving the third in front of you. The same process of elimination will find the counterfeit coin.

Difficulty ★★★☆☆ Popularity ★★★★★

Two batsman each on 94 runs. Seven runs needed to win in last 3 balls. Both make 100*. How?

Answer & Explanation

Batsman hit six and gone retired hurt while the new batsman come to play and get runout for his wicket and the other batsman hit six and made both century and team win..

Difficulty ★★☆☆☆ Popularity ★★★★★

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You dontknow the identity of the two.You can ask only one question to go out from there. What should you ask?

Answer & Explanation

If you ask the guard who always tells the truth, he would tell you the other guard would point you to the door of death. If you ask the guard who always lies, he would tell you the opposite door of the truth-telling guard and point you to the door of death. In either case, both guards will point to the door of death so you should choose the other one.

Difficulty ★★★★☆ Popularity ★★★★☆

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

Answer & Explanation

17 mins

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.

LetÃ¢€™s brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So letÃ¢€™s put all this together.

1 and 2 go cross

2 comes back

7 and 10 go across

1 comes back

1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 mins

Difficulty ★★★★☆ Popularity ★★★★★

Using eight eights and addition only, can you make 1000?

Answer & Explanation

888 + 88 + 8 + 8 + 8 = 1000

Difficulty ★★★★☆ Popularity ★★★★☆

At the local model boat club, four friends were talking about their boats.

There were a total of eight boats, two in each colour, red, green, blue and yellow. Each friend owned two boats. No friend had two boats of the same colour.

Alan didn't have a yellow boat. Brian didn't have a red boat, but did have a green one. One of the friends had a yellow boat and a blue boat and another friend had a green boat and a blue boat. Charles had a yellow boat. Darren had a blue boat, but didn't have a green one.

Can you work out which friend had which coloured boats?

Answer & Explanation

Alan had a red boat and a green boat.

Brian had a green boat and a blue boat.

Charles had a yellow boat and a red boat.

Darren had a blue boat and a yellow boat.

Difficulty ★★★★☆ Popularity ★★★★☆

A man who lives on the tenth floor takes the elevator down to the first floor every morning and goes to work. In the evening, when he comes back; on a rainy day, or if there are other people in the elevator, he goes to his floor directly. Otherwise, he goes to the seventh floor and walks up three flights of stairs to his apartment.

Can you explain why?

Answer & Explanation

The man is a of short stature. He can't reach the upper elevator buttons, but can push is with his umbrella.

Difficulty ★★☆☆☆ Popularity ★★★★☆

Six jugs are in a row.

The first three are filled with coke, and the last three are empty.

By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Answer & Explanation

Move and then pour all coke from second glass to fifth glass.

Difficulty ★★★★☆ Popularity ★★★★☆

Mr. Black, Mr. Gray, and Mr. White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr. Black, who hits his shot 1/3 of the time, gets to shoot first. Mr. Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr. White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. If you are Mr. Black, where should you shoot first for the highest chance of survival?

Answer & Explanation

He should shoot at the ground.

If Mr. Black shoots the ground, it is Mr. Gray's turn. Mr. Gray would rather shoot at Mr. White than Mr. Black, because he is better. If Mr. Gray kills Mr. White, it is just Mr. Black and Mr. Gray left, giving Mr. Black a fair chance of winning. If Mr. Gray does not kill Mr. White, it is Mr. White's turn. He would rather shoot at Mr. Gray and will definitely kill him. Even though it is now Mr. Black against Mr. White, Mr. Black has a better chance of winning than before.

Difficulty ★★★★★ Popularity ★★★★☆

If Susan is 10, Arabella is 20, and Jim and Neal are both 5, but Richard is 10, how much is Jennifer by the same system?

Answer & Explanation

Jennifer is fifteen, in a system that awards five for each syllable.

Difficulty ★★★★☆ Popularity ★★★★★

Four people need to cross a dark river at night.They have only one torch and the river is too risky to cross without the tourch. if all people cross simultanoesly then torch light wont be sufficient.Speed of each person of crossing the river is different.cross time for each person is 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the river ?

Answer & Explanation

The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.

Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.

1 and 2 go cross

2 comes back

7 and 10 go across

1 comes back

1 and 2 go across (done)

Total time = 2 + 2 + 10 + 1 + 2 = 17 mins

Difficulty ★★★★☆ Popularity ★★★★★

Two old friends, Jack and Bill, meet after a long time.

Three kids

Jack: Hey, how are you man?

Bill: Not bad, got married and I have three kids now.

Jack: That’s awesome. How old are they?

Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.

Jack: Cool… But I still don’t know.

Bill: My eldest kid just started taking piano lessons.

Jack: Oh now I get it.

How old are Bill’s kids?

Answer & Explanation

3,3,8

Lets break it down. The product of their ages is 72. So what are the possible choices?

2, 2, 18 sum(2, 2, 18) = 22

2, 4, 9 sum(2, 4, 9) = 15

2, 6, 6 sum(2, 6, 6) = 14

2, 3, 12 sum(2, 3, 12) = 17

3, 4, 6 sum(3, 4, 6) = 13

3, 3, 8 sum(3, 3, 8 ) = 14

1, 8, 9 sum(1,8,9) = 18

1, 3, 24 sum(1, 3, 24) = 28

1, 4, 18 sum(1, 4, 18) = 23

1, 2, 36 sum(1, 2, 36) = 39

1, 6, 12 sum(1, 6, 12) = 19

The sum of their ages is the same as your birth date. That could be anything from 1 to 31 but the fact that Jack was unable to find out the ages, it means there are two or more combinations with the same sum. From the choices above, only two of them are possible now.

2, 6, 6 sum(2, 6, 6) = 14

3, 3, 8 sum(3, 3, 8 ) = 14

Since the eldest kid is taking piano lessons, we can eliminate combination 1 since there are two eldest ones. The answer is 3, 3 and 8.

Difficulty ★★★★★ Popularity ★★★★☆

You are the ruler of a medieval empire and you are about to have a celebration tomorrow. The celebration is the most important party you have ever hosted. You've got 1000 bottles of wine you were planning to open for the celebration, but you find out that one of them is poisoned.

The poison exhibits no symptoms until death. Death occurs within ten to twenty hours after consuming even the minutest amount of poison.

You have over a thousand slaves at your disposal and just under 24 hours to determine which single bottle is poisoned.

You have a handful of prisoners about to be executed, and it would mar your celebration to have anyone else killed.

What is the smallest number of prisoners you must have to drink from the bottles to be absolutely sure to find the poisoned bottle within 24 hours?

Answer & Explanation

10 prisoners must sample the wine. Bonus points if you worked out a way to ensure than no more than 8 prisoners die. Number all bottles using binary digits. Assign each prisoner to one of the binary flags. Prisoners must take a sip from each bottle where their binary flag is set. Here is how you would find one poisoned bottle out of eight total bottles of wine. Bottle 1 Bottle 2 Bottle 3 Bottle 4 Bottle 5 Bottle 6 Bottle 7 Bottle 8 Prisoner A X X X X Prisoner B X X X X Prisoner C X X X X In the above example, if all prisoners die, bottle 8 is bad. If none die, bottle 1 is bad. If A & B dies, bottle 4 is bad. With ten people there are 1024 unique combinations so you could test up to 1024 bottles of wine. Each of the ten prisoners will take a small sip from about 500 bottles. Each sip should take no longer than 30 seconds and should be a very small amount. Small sips not only leave more wine for guests. Small sips also avoid death by alcohol poisoning. As long as each prisoner is administered about a millilitre from each bottle, they will only consume the equivalent of about one bottle of wine each. Each prisoner will have at least a fifty percent chance of living. There is only one binary combination where all prisoners must sip from the wine. If there are ten prisoners then there are ten more combinations where all but one prisoner must sip from the wine. By avoiding these two types of combinations you can ensure no more than 8 prisoners die. One viewer felt that this solution was in flagrant contempt of restaurant etiquette. The emperor paid for this wine, so there should be no need to prove to the guests that wine is the same as the label. I am not even sure if ancient wine even came with labels affixed. However, it is true that after leaving the wine open for a day, that this medieval wine will taste more like vinegar than it ever did. C'est la vie.

Difficulty ★★★☆☆ Popularity ★★★★☆

A newspaper is supposed to have 60 pages

but pages 24 and 41 are missing.

Which other pages won't be there?

Answer & Explanation

Pages 19, 20, 23, 37, 38, & 42 will also be missing

Difficulty ★★★★★ Popularity ★★★★★

Distances from you to certain cities are written below.

BERLIN 200 miles

PARIS 300 miles

ROME 400 milesAMSTERDAM 300 miles

CARDIFF ??? miles

How far should it be to Cardiff ?

Answer & Explanation

100 miles. Each vowel is worth 300 and each consonant is worth -100. These are totalled in each city name to give the distance

I am an odd number; take away an alphabet and I become even. What number am I?

Why did Mayank Kapoor keep his trumpet in the fridge?

Decode below three cipher riddles

26 L of the A

7 D of the W

1000 Y in a M

Two girls were born to the same mother, on the same day, at the same time, in the same month and year and yet they're not twins. How can this be ?

The sum of a mother, her baby and her dog weight is 170 pounds.

How much does the baby weigh if the mother weighs 100 pounds more than the combined weight of the baby and the dog,and the dog weighs 60 percent less than the baby?

Use the digits 1, 2, 3, 4, 5 and 6 once only, in this multiplication sum to make it correct.

? ?

x ?

-------

? ? ?

Teacher ask the student 'Why are you standing on that chair in music class ?'.

what did student replied ?

A girl, at the funeral of her mother, met a guy whom she did not know. She fell for him and just kept looking at him.Sometime later she realized that the guy is gone and she forgot to take the number of the guy and now she can't find him. A few days later she killed her elder brother.

Question: What is her motive in killing her brother ?

What is the largest number you can write with just 3 digits ?

What Come next in sequence

1 , 4 , 5 , 6 , 7 , 9 , 11 ?

Baseball bat and ball cost $50.

If the bat cost $49 more than the ball.

What is the cost of each ?

Tanu gupta was out for a walk when it started to rain. She did not have an umbrella and she wasn't wearing any hat. Her clothes were soaked yet not a single hair on her head got wet. How could this happen?

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

What word can be written forward backward or upside down and can still be read from left to right?

I saw a Jeans for Rs97. I dont have enough money , so i borrowed Rs50 from my mom and 50 from my dad = Rs100. I bought the jeans, and had Rs3 change. I gave dad Rs1 and my mom Rs1 and kept the other Rs1 for myself. Now I owe my mum Rs49 and my dad Rs49. 49+49 = 98 + my Rs1 = 99. Where is the missing Rs1?

Difficulty ★★☆☆☆ Popularity ★★★★★

What does this say: T RN?

Difficulty ★★☆☆☆ Popularity ★★★★★

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You dontknow the identity of the two.You can ask only one question to go out from there. What should you ask?

Difficulty ★★☆☆☆ Popularity ★★★★★

Bay of Bengal is in which state?

Difficulty ★★☆☆☆ Popularity ★★★★☆

What part of the Turkey has the most feathers?

Difficulty ★★☆☆☆ Popularity ★★★★☆

Can you find the mistake ?

Difficulty ★★☆☆☆ Popularity ★★★★☆

If you multiply all the numbers on the telephone, what is the answer?

Difficulty ★★☆☆☆ Popularity ★★★★☆

A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed to a hospital, suffering from injuries. But the attending surgeon at the hospital, upon seeing the boy, says 'I cannot operate. This boy is my son.' How is this situation explained?

Difficulty ★★☆☆☆ Popularity ★★★★☆

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Difficulty ★★☆☆☆ Popularity ★★★★☆

I am the owner of a birds store. If I put in one bird per cage, I have one bird too many. If I put in two bird per cage, I have one cage too many. How many cages and birds do I have?

Difficulty ★☆☆☆☆ Popularity ★★★★☆

A bus driver was heading down a street in Delhi. He went right past a stop sign without stopping, he turned left where there was a 'no left turn' sign and he went the wrong way on a one-way street. Then he went on the left side of the road past a cop car. Still - he didn't break any traffic laws. Why not?

Difficulty ★★☆☆☆ Popularity ★★★★☆

The Little ant always confused.Do you know why ?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

What can you catch but not throw?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

I have streets but no pavement,

I have cities but no buildings,

I have forests but no trees,

I have rivers yet no water.

What am I?

Difficulty ★☆☆☆☆ Popularity ★★★☆☆

Identify the hidden meaning behind this picture ?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

Fred can eat 27 chocolates in a hour, Alice can eat 2 chocolates in 10 minutes, and Kelly can eat 7 chocolates in 20 minutes. How long will it take them to share and eat a large box of 120 chocolates whilst watching a movie?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

Kareena is older than Bipasha. Bipasha is younger than Karishma and younger than Katrina. Katrina is older than Kareena and Alonso, who are older than Karishma.If Alonso and Kareena are twins, who's oldest?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

What demands an answer, but asks no questions

Difficulty ★☆☆☆☆ Popularity ★★★☆☆

Why is a river so rich ?

Difficulty ★☆☆☆☆ Popularity ★★★☆☆

I look at you, you look at me I raise my right,you raise your left. What am I ?

Difficulty ★★☆☆☆ Popularity ★★★☆☆

Two ladies played cards for candy; the winner received one piece per game from the loser. When it was time for one of the ladies to go home, one lady had won three games, while the other lady had won three new pieces of candy.

How many individual games had they played?

I have forests, but no trees.

I have lakes, but no water.

I have roads, but no cars.

What Am I?

Manoj Singh left on a horse on Thursday , was gone for two days, and came back on Thursday How did that happen?

Identify the next two numbers in this series?

101, 112, 131, 415, 161, 718, ???, ???

What do you get if you add 2 to 200 four times?

Every words stands for unique digit that makes the arithmetic equation true

SEVEN + SEVEN + SIX = TWENTY.

What are the digits ?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

Why do Chinese men eat more rice than Japanese men do

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