parmarankita26 wrote:

I don't agree with the explanation. If the Number is 30 and you substract it by 9 you get 21 and hence the tens digit is 2; Similarly the number 29 - 9 =20 and the tens digit is 2 again

Hi,

this is exactly the reason why statement II is not sufficient alone - you should take N as initial value 30 and 29 and not the answer N-9..

The explanation also is the same so why you don't agree to it?

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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

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