Thursday, October 1, 2009

Problem 53 - GMAT Number Properties


2 comments:

  1. i think OA D
    first 111 prime nos = only 1 even prime (2) + 100 odd primes...

    addiing 100 odd nos =>
    1st odd + 2nd odd = even + 3rd odd = odd + 4th odd = even
    thus on adding
    2nd number = e
    3rd numer = o
    4th number = e
    5th number = o....this trend contd....on adding each even numbered digit you get result even....thus....on adding 100th digit we get even result ...then adding odd (2) will result in e+e = e.....hence x is even

    hence eqn becomes 1-1+1-1+1 = 1..OA D

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  2. Yep, answer is D, good job Bhushan, they key is to see that x is even, as you said, and then you have +1 -1 + 1 -1 +1 = 1

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