Question

The first and last terms of an A.P. are 1 & 11 .if there sum is 36,then the no. of terms will be?

Answer 1

Answer:

a=1

l=11

sn=36

sn=n/2(a+l)=36

n(1+11)=36*2

n*12=72

n=72/12

n=6