Hello Paramjit

Answer is 960

As it is a arithmetic progression.( Ap series).

Formula for the sum of all terms is

Sum= (n/2) * ( 2*a + (n-1)* d)

Where n= number of terms

a = first term of series

d = difference between any two consecutive terms.

Hi paramjit , its problem of arithmetic progression. So use the formula mentioned below

n/2(2a+(n-1)d)

Thanks.