**Impossible Maths Number Riddle - 20 February**

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube ?

* Its a popular maths trivia riddle.

**For Solution :**Click Here

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

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube ?

* Its a popular maths trivia riddle.

Subscribe to:
Post Comments (Atom)

Difficulty Level 3/5
(743)
Logic Puzzles
(492)
Difficulty Level 4/5
(466)
Riddles
(366)
Difficulty Level 2/5
(358)
Maths Puzzles
(350)
Picture Puzzles
(344)
Trick Teasers
(285)
Popular Puzzles
(215)
Rebus Puzzles
(156)
Humor Puzzles
(152)
Series Puzzles
(127)
Interview Puzzle
(126)
What Word Am I
(99)
Difficulty Level 1/5
(90)
Equation Puzzles
(76)
Trivia
(76)
Mystery Puzzles
(73)
Difficulty level 5/5
(54)
Murder Mystery Puzzles
(43)
Who Am I
(42)
Square Count
(40)
Probability Puzzles
(39)
Algebra
(34)
IAS-EXAMS
(34)
Cipher Puzzles
(32)
Science Puzzles
(30)
Situation Puzzles
(28)
Puzzles of Age
(21)
MatchSticks-Riddles
(19)
Read Between Lines Puzzles
(18)
Google Interview Puzzle
(17)
Microsoft Interview Puzzles
(15)
statement
(15)
Time Distance Problem
(14)
Odd One Out
(13)
Relationship Puzzles
(11)
Cards
(10)
Story Puzzles
(10)
Paradox Puzzles
(9)
Classic
(6)
Directional Puzzles
(6)
Best Of 2011
(5)
clever
(5)
Brain-Twister
(4)
Mind Games
(4)
Analytical
(3)
What Does This Text Mean
(3)
chess
(3)
CHALLENGING
(2)
Double Meaning
(2)
Acronym
(1)
Measure
(1)
Suduko
(1)
Video Riddle
(1)
coin-Puzzles
(1)
m
(1)
pop
(1)
triv
(1)

x^3 - 1 = (x - 1)(x^2 + x + 1)

ReplyDeleteThis suggests that x^3 - 1 cannot be prime when x - 1 > 1, or x > 2, since x - 1 is a factor of x^3 - 1.

When x = 2, we have the example given (7 and 8). All larger cubes cannot be preceded by a prime since x > 2 in those cases.

since for being prime no one of the right side equation should be 1.

ReplyDelete[x^3-1=(x-1)(x^2+x+1)]

i.e. x-1=1 or x^2+x+1=1

which gives x=-1,0,2

in this -1,0 the cube comes to be the same as -1 and 0, which does not have the preceeding no -2,-1 which is not prime, so only one answer can be possible that is 2.

2^3=8

8-1=7

This comment has been removed by the author.

ReplyDeletebut 63 exists right, which is followed by 64,a cube..............!!!!

ReplyDelete63/9=7

Delete