Set A contains all the even numbers between 10 and 50 inclusive. Set B contains all the even numbers between 110 and 150 inclusive. What is the difference between the sum of elements of set B and the sum of the elements of set A?  Select:
A) 2100 B) 2550 C) 5050 D) 6275 E) 11325

Rationale: "set a contains 10 , 12,14 , 16 . . . 50 set b contains 110 , 112 , 114 . . . 150 number of terms in each set = 21 difference between corresponding terms in set a and b = 100 difference between sum of set b and set a = 100 * 21 = 2100 answer a"
Answer: A