What is the positive difference between the sum of the first 20 positive even integers and the sum of the first 15 positive odd integers?

S=[F + L] / 2 x N, Where S=Sum, F=First term, L=Last term, N=Number of terms.

S=[2 + 40] / 2 x 20

S =420 - Sum of first 20 even integers.

 

S =[ 1  + 29] / 2 x 15

S =225 - Sum of first 15 odd integers.

 

420 - 225 =195 - The difference