division

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division

by Chrystelle » Fri Jan 12, 2007 7:00 am
What is the remainder when x is divided by 12?
1) (x-3) is divisible by 4
2) (x-27) is divisible by 36

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by thankont » Fri Jan 12, 2007 8:16 am
1) x-3 = 4k => x = 4k + 3 put k=3,4,5,6, etc. and get 15,19, 23 etc so remainders (when divided by 12) are 3, 7, 11 (different so A is insuff.)
2) x-27 = 36k => x= 36k+27 = 3*12k+27 = 3*12k+3*12+3 =
=3m+3 so remainder is 3 when x is divided by 12 (same so B sufficient)

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by Chrystelle » Sun Jan 14, 2007 9:39 am
thanks thankot