Find the sum of squares of all numbers between 10 and 70 and which are divisible by 4.

- November 3rd 2010, 07:26 PMrickrishavsum of squares of all numbers between 10 and 70 and which are divisible by 4.
Find the sum of squares of all numbers between 10 and 70 and which are divisible by 4.

- November 4th 2010, 08:19 AMWilmer
All evens are divisible by 4; so "sum of even squares":

n = 70/2 = 35; f = (10-2)/2 = 4

2n(n+1)(2n+1)/3 - 2f(f+1)(2f+1)/3 = 59640 - 120 = 59520

"See" that? - November 4th 2010, 10:13 AMSoroban
Hello, rickrishav!

I hope I interpreted the problem correctly . . .

Quote:

Find the sum of squares of all integers between 10 and 70 which are divisible by 4.

The integers between 10 and 70 which are multiple of 4 are:

. .

The sum of their squares is:

. .

. . . .

. . . .

. . . . .**

. . . .

. . . .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

**

The sum of the first squares is:

. .