Wednesday, August 10, 2005

Maths is fun

Rex Hubbard writes:
Try to solve this problem mentally and in less than six steps.

(5^6) - 1 is divisible by:

A) 58
B) 59
C) 61
D) 62
E) 86

I find that solving math problems can be surprisingly satisfying. I'll put my solution in the comments, in case any readers want to try it for themselves first.

3 comments:

  1. The difference of two squares:
    5^6 - 1 = (5^3 - 1)(5^3 + 1)

    Left hand factor = 124 = 62 * 2

    Thus the answer is "D".

    ReplyDelete
  2. How long did this take you? I came to the same conclusion in about 2mins.

    ReplyDelete
  3. Yeah, around a minute, I think.

    ReplyDelete

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