What is the units digit of positive integer p?

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What is the units digit of positive integer p?

by AAPL » Fri Jun 15, 2018 2:06 pm

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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.

The OA is A.

I don't understand why A is the correct answer.

Is not possible that p equals 8 so 8 divided by 10 is 0 with remainder 8?

So, in this case, we would have p = 8 or P =108 and thus Statement 1 would be insufficient.

Can anyone help, please? Thanks!
Source: — Data Sufficiency |

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by [email protected] » Fri Jun 15, 2018 5:39 pm

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Hi AAPL,

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

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