adkikani wrote:

Hi

chetan2u Bunuel PKN gmatbusters amanvermagmat Abhishek009 VeritasKarishmaI could not understand above solution. Could you elaborate?

Hi

adkikani,

Question stem:- We need to find out an unique value of z.

Given, y,z, and b are positive integers greater than 1.

St1:-

\(y^3=\)A perfect cube*\(z^b<\) perfect square less than 100( \(2^2, 3^2, 4^2,5^2, 6^2, 7^2, 8^2, 9^2\))

Since y is an integer greater than 1, hence the possible values of \(y^3\)\(* z^b\):

a) \(2^3*8=8^2=64<100\) (A PERFECT SQUARE). KEEP

b) \(3^3*

3^1=9^2\)<100( (A PERFECT SQUARE), However, b>1.

DISCARD this case.

So, we have an unique value of z from (a).

Sufficient.

St2:- \(y^3*z^b=x^3\), where x is an integer.

Here, there are no restrictions on the values of the variables x,y,z, and b.

Hence, we can have numerous values of z.

Insufficient.

Ans. (A)

P.S:- You may raise specific queries(if any)

_________________

Regards,

PKN

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