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Bunuel
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(1) t=p∗q; p and q have no common prime factors.
p and q are coprimes, let p=2, q=3 then no. of factors of t are 4
When p=6 and q=7; no. of factors of t are 8. Insufficient.

(2) t=p∗q; p and q each have exactly 5 positive integer factors.
As p and q are different positive integers and each have 5 factors, then number of factors of t are 25. Sufficient.

B is correct.
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Hi,

1. t = p * q where p and q have no common prime factors.
That means they are relatively prime or co-prime numbers.
let p = 40 => \(2^3\) * 5
and q = 21 => 3 * 7
thus t = \(2^3\) * 3 * 5 *7
so, t can have 32 factors.
Sufficient.

2. t = p * q where p and q have exactly 5 positive integer factors.
Only the SQUARES of integers have an ODD number of positive factors.
so, let p = 16 => \(2^4\) and q = 81 =>\(3^4\)
so, t = \(2^4\)* \(3^4\)
total factor = 25
Sufficient.

The answer is D.

Please hit kudos if you like the solution.
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If t, p, and q are different positive integers, ( note the word different)

(1) t=p∗qt=p∗q; p and q have no common prime factors. clearly insufficient
(2) t=p∗qt=p∗q; p and q each have exactly 5 positive integer factors. so p and q are perfect squares, it give rise to two possibilities either p = q or p not equal to q, question says they are different

so different perfect squares results in x^4 * y^4 hence total factors is 5 * 5 = 25 for t so b alone is sufficient

ans B
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Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

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