Difficulty ★★★☆☆ Popularity ★★★★☆

What is the probability of getting five Monday in a 31-days month ?

Difficulty ★★★☆☆ Popularity ★★★☆☆

kukki and fukki are a married couple (dont ask me who he is and who she is) :)

They have two kids, one of them is a girl. Assume safely that the probability of each gender is 1/2.

What is the probability that the other kid is also a girl?

Hint: It is not 1/2 as you would first think.

Difficulty ★★☆☆☆ Popularity ★★★☆☆

I throw two dice simultaneously.

What is the probability of getting sum as 9 of the two numbers shown ?

Difficulty ★★★★☆ Popularity ★★★★★

What is the probability of choosing the correct answer at random from the options below.

a) 1/4

b) 1/2

c) 1

d) 1/4

Difficulty ★★★☆☆ Popularity ★★★★★

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.

After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

Difficulty ★★☆☆☆ Popularity ★★★★★

Henry has been caught stealing cattle, and is brought into town for justice. The judge is his ex-wife Gretchen, who wants to show him some sympathy, but the law clearly calls for two shots to be taken at Henry from close range. To make things a little better for Henry, Gretchen tells him she will place two bullets into a six-chambered revolver in successive order. She will spin the chamber, close it, and take one shot. If Henry is still alive, she will then either take another shot, or spin the chamber again before shooting.

Henry is a bit incredulous that his own ex-wife would carry out the punishment, and a bit sad that she was always such a rule follower. He steels himself as Gretchen loads the chambers, spins the revolver, and pulls the trigger. Whew! It was blank. Then Gretchen asks, 'Do you want me to pull the trigger again, or should I spin the chamber a second time before pulling the trigger?'

What should Henry choose?

Difficulty ★★★★☆ Popularity ★★★★☆

Bruna was first to arrive at a 100 seat theater.

She forgot her seat number and picks a random seat for herself.

After this, every single person who get to the theater sits on his seat if its available else chooses any available seat at random.

Neymar is last to enter the theater and 99 seats were occupied.

Whats the probability what Neymar gets to sit in his own seat ?

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?

Difficulty ★★★★☆ Popularity ★★★☆☆

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Difficulty ★★★★☆ Popularity ★★☆☆☆

Three people enter a room and have a green or blue hat placed on their head. They cannot see their own hat, but can see the other hats.

The color of each hat is purely random. They could all be green, or blue, or any combination of green and blue.

They need to guess their own hat color by writing it on a piece of paper, or they can write 'pass'.

They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.

If at least one of them guesses correctly they win $50,000 each, but if anyone guess incorrectly they all get nothing.

What is the best strategy?