DS - integers

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Posted by: dauntless18

. If x and y are integers between 10 and 99, inclusive, is X-Y/9 an integer?
(1) x and y have the same two digits, but in reverse order.
(2) The tens’ digit of x is 2 more than the units digit, and the tens digit of y is 2 less than the units digit

A
B
C
D
E

from option A
Let X = 10a +b then Y = 10b +a

X-Y/9 = 9 * (a-b)/ 9 this is sufficient

from option B
X = 10 (a+2) + a = 11a+20
Y = 10 (b-2) + b = 11b - 20
so X-Y/ 9 = 11(a-b) + 40 / 9 ... for some values of (a-b) it is div by 9 ,for some it is nt.


ex
a-b=-1 29/9 Not divisible
a-b=-2 18/9 Yes

Ans A

agree A .