Bunuel wrote:

If b is selected at random from Set A, what is the probability that b - 13 will be a prime number?

(1) A is a set of 10 integers

(2) A is a set of prime numbers

Kudos for a correct solution.

First thing to note here from question stem is that 'b' cannot be less than 13 as the smallest prime in history of number system is a positive number (i.e. 2 ) .

option A :

set of 10 integers

----->1,2,3,4,5,6,7,8,9,10

choose any number , b-13 will never be prime.

------>15,16,17,18,19,20,,21,22,21,22

we will get handful of primes if we choose 'b' from this set and do b-13 .

2 Answers , so A is NS.

option B :

A is a set of prime numbers, if prime numbers are less than 13 then the probability is 0 as we will get a -ive number (b-13) .

however, if prime numbers are greater than 13 then O-O will always be EVEN. so again the probability is 0.

Option B is sufficient .

Answer: B

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Lucky

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