The sum of the squares of the first 15 positive integers (1^2 + 2^2 + 3^2 + . . . + 15^2) is equal to 1240. What is the sum of the squares of the second 15 positive integers (16^2 + 17^2 + 18^2 + . . . + 30^2) ?  Select.
A) 2480
B) 3490
C) 6785
D) 8215
E) 9255
sum of square of n numbers is found using the formula [n (n+1) (2n+1)]/6   we have sum of 1st 15 numbers = 1240   we need to find sum of squares from 16 to 30 which is = sum of squares of 1st 30 +ve integers - sum of squares of 1st 15 +ve integers.   we will get 8215 - 8215;ANSWER:8215
<result>D</result>
The sum of the squares of the first 15 positive integers (1^2 + 2^2 + 3^2 + . . . + 15^2) is equal to 1240. What is the sum of the squares of the second 15 positive integers (16^2 + 17^2 + 18^2 + . . . + 30^2) ?