If x and y are prime numbers such that x > y > 5, then x^2 − y^2 must be divisible by which one of the following numbers?
Pick:
A) 3 B) 7 C) 5 D) 9 E) 12
If x=7 and y=5, then x^2-y^2=24 and 24 is divisible only by 12 from the options, thus it must be correct.   Answer: 12.
<result>E</result>
If x and y are prime numbers such that x > y > 5, then x^2 − y^2 must be divisible by which one of the following numbers?