Hi,

1) simple logic should tell us that answer should be near but LESS than 1/2..
As we are dealing with duplicate patterns.. 1 and 6..... 2 and 5...3 and 4...
C should be the guess..
Why it should be near half is in the method below.

2) there can be six numbers in first throw and six in second , so ways = 6*6*=36..

Now if 1 is in first throw, any number in 2nd throw except 1 itself will give you ans YES, so 5 throw..
But in 2, all except 1 and itself will bE so 6-2=4 ways..
Similarly 3,2,1 and 0 for number 4,3,2,and 1respectively in first throw..
Possible ways=5+4+3+2+1+0=15..

Prob =15/36=5/12..
C
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1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

exactly my approach...yet I used approximations.
the odds should be slightly less than 1/2
A is too little
B is too big
C is close
D is too big
E is too big.

C remains

Probability of getting it is 1/2 minus the probability of getting the same number on both throws which is 1/12.

(1/2) - (1/12) = 5/12

Option C