If x is a sum of all even integers on the interval 13...63 and y is their number, what is the GCD (x, y)?	Choose the correct choice from the following.
A) 1  B) 13  C) 26  D) 25  E) 1014

Rationale: x = 14 + 16 + . . . + 62 = ( largest + smallest ) / 2 * ( # of terms ) = ( 14 + 62 ) / 2 * 25 = 38 * 25 . gcd of 25 and 39 * 25 is 25 . answer : d .
Answer: D