If P is a positive integer, then P4 has how many digits?

Question

If P is a positive integer, then  P^4  has how many digits?

(1)  P^2  has 2 digits which are from the set {1, 2, 5 and 6}.

(2) P is a single digit number.

chetan2u · Answer

If P is a positive integer, then  P^4  has how many digits?

(1)  P^2  has 2 digits which are from the set {1, 2, 5 and 6}.
Only 16 and 25 are squares, so P is 4 or 5.
So  P^4  can be 256 or 625.
In both cases, it has 4 digits. 
Sufficient

(2) P is a single digit number.
If P is 2,  P^4  has 2 digits. 
If P is 5, then 3 digits. 
Insufficient

A

Jitu20 · Answer

Wrong, answer is C, because P^2 has 2 digits which are from the set{1, 2, 5 and 6}, even 256 is a perfect square. Therefore answer is C.

chetan2u · Answer

Not only 256, 625 is also a square. But both 256 and 625 are 3-digits. 
We are looking for 2 digits.

Jitu20 · Answer

According to the question it says P^2 has two digits which are from the set {1,2,5 and 6} but it does not say P^2 is a two digit number which is from the set {1,2,5,6}

chetan2u · Answer

The question may not be worded properly but still your answer as C is wrong for two reasons.
1) WHICH introduces a non essential modifier on GMAT, so 'P^2 has two digits' means p^2 is a 2-digit number. Of course, it should have been written accordingly. 
HAD it been - P^2 has two digits that are from..., you could have read the question some other way.
2) When you write 256, you are choosing 3 digits 2, 5 and 6 from the set {1, 2, 5, 6}

The question although not well written will still have A as the answer.

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If P is a positive integer, then P4 has how many digits?

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GMAT Data Sufficiency (DS) Questions

If P is a positive integer, then P4 has how many digits?

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