Question

3,10,17,24.....AP. Find the sum of its 8 terms​

Answer 1

we have

a=3 , d=7 , n =8

now,

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

=8/2[2*3+(8-1)7]

=4(6+49)

=4*55

=220

hence, sum of 8 terms =220