Data Sufficiency

BTGmoderatorDC wrote:What is the units digit of positive integer p?

(1) When p is divided by 10, the remainder is 8
(2) When p is divided by 11, the remainder is 8

We have to get the units digit of positive integer p.

Let's take each statement one by one.

(1) When p is divided by 10, the remainder is 8.

Say the quotient is q, then we have p = 10q + 8, where q = a non-negative integer

For q = 0, 1, 2, 3,..., we have p = 8, 18, 28, 38, ... We see that the units digit of positive integer p is 8. Sufficient.

(2) When p is divided by 11, the remainder is 8.

Say the quotient is m, then we have p = 11m + 8, where m = a non-negative integer

For m = 0, 1, 2, 3,..., we have p = 8, 19, 30, 41, ... We see that the units digit of positive integer p is not the same. Insufficient.

The correct answer: A

Hope this helps!

-Jay
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Hi All,

We're told that P is an integer. We're asked for the UNITS DIGIT of P (re: the "ones digit"). This question can be solved by TESTing VALUES.

1) When P is divided by 10, the remainder is 8.

IF....
P = 8, then 8/10 = 0 r 8 and the answer to the question is 8
P = 18, then 18/10 = 1 r 8 and the answer to the question is 8
P = 28, then 28/10 = 2 r 8 and the answer to the question is 8
Etc.
Since the question asks for the UNITS DIGIT of P, the answer to the question will ALWAYS be 8.
Fact 1 is SUFFICIENT

(2) When P is divided by 11, the remainder is 8.

IF....
P = 8, then 8/11 = 0 r 8 and the answer to the question is 8
P = 19, then 19/11 = 1 r 8 and the answer to the question is 9
Fact 2 is INSUFFICIENT

Final Answer: A

GMAT assassins aren't born, they're made,
Rich