5th grader math rocks! problem - r u smarter than a 5th grader?

thisway 2010-02-08 21:28:11 ( reads)

Prove that the number 3 + 3x3 + 3x3x3 + 3x3x3x3 + .... + 3 to the power of 60 is divisible by 2x2x2x3x5x11x11x13
Hints: 1+3+3x3 = 13; 1+3+3x3+3x3x3 = 40; 1+3+3x3+3x3x3+3x3x3x3 = 121

跟帖(6)

Jinjing

2010-02-09 17:08:48

回复：5th grader math rocks! problem - r u smarter than a 5th grade

一用户

2010-02-09 19:00:04

brilliant

pj

2010-02-12 06:43:57

it's harder without the HINT.

Jinjing

2010-02-12 08:22:13

回复：it's harder without the HINT.

hisch

2010-02-18 16:08:33

回复：5th grader math rocks! problem - r u smarter than a 5th grade

hisch

2010-02-18 16:10:06

Different Proof