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=>

There are \(8\) prime numbers between \(1\) and \(21\), inclusive: \(2, 3, 5, 7, 11, 13, 17\) and \(19\).
So, there are 8C2 ways of selecting \(2\) numbers from these \(8\) prime numbers.
There are 21C2 ways of selecting \(2\) numbers from the \(21\) numbers from \(1\) to \(21\), inclusive.
Thus, the probability that the \(2\) selected numbers are prime numbers is 8C2 / 21C2 = ( 8*7 / 1*2) / ( 21*20 / 1*2 ) = 8*7 / 21*20 = 2/15.

Therefore, the answer is A.

Answer: A
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I got it right but the question doesn't specify if repetitions are allowed.
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Hello from the GMAT Club BumpBot!

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