SOLUTION: Hi please help me with this problem- if p and q are two prime numbers such that p < q < 50, then in how many cases would (q+p) be also a prime number.

Question 730320: Hi please help me with this problem- if p and q are two prime numbers such that p < q < 50, then in how many cases would (q+p) be also a prime number.
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

This looks a lot more difficult than it really is. First thing to note: There is only one even prime, namely 2, the smallest prime. Second thing to note, the sum of two odd numbers is always even, so the only way that

could possibly be prime is if

. The primes less than 50 are 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47

So

2 + 3 = 5 is prime

2 + 5 = 7 is prime

2 + 7 = 9 is not prime

2 + 11 = 13 is prime ...

and so on. You can calculate the other 10 sums and decide whether they are prime or not.

John

Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it

The Out Campaign: Scarlet Letter of Atheism

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