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from stat 1 , p can be 2 and 2p+1 will be prime, or p can be 7 and 2p+1 is not prime. insuff.

from stat 2, p can be 1 and 2p+1 is prime, or, p can be 4 and 2p+1 is not prime. insuff.

together, consider 11 which satisfies both conditions. in this case, 2p+1 is prime. now consider 31, which also satisfies both cases. Here, 2p+1 is not prime. insuff.

If p is a positive integer, is 2p + 1 prime? 1. p is prime 2. units digit of p is not prime

the question is not up to the gmat standard. its statememnts are contradictory to each other. so either the posting is wrong or some information is missing. _________________

If p is a positive integer, is 2p + 1 prime? 1. p is prime 2. units digit of p is not prime

the question is not up to the gmat standard. its statememnts are contradictory to each other. so either the posting is wrong or some information is missing.

why do you say that?

let's consider 29: it is prime and its unit digit is not prime. the question is from gmatclub challenges

If p is a positive integer, is 2p + 1 prime?1. p is prime 2. units digit of p is not prime

the question is not up to the gmat standard. its statememnts are contradictory to each other. so either the posting is wrong or some information is missing.

why do you say that?let's consider 29: it is prime and its unit digit is not prime. the question is from gmatclub challenges

lol.....seems i need to be refreshed. _________________