Question

If nth term of an A.P. is 2n+1/3 then what is the sum of first 22 terms ?

Answer 1

Answer:

nth term (an)=2n+1/3

Let n=1

2(1)+1/3

2+1/3

(6+1)/3

7/3

A1=7/3

Let n=2

2(2)+1/3

4+1/3

(12+1)/3

13/3

A2=13/3

D=A2-A1

=13/3-7/3

=6/3

=2

S22, n=22

S22=22/2(2×7/3+21×2)

=11(14/3+42)

=11(14+126)/3

=11(140)/3

=11×46.6

=512.6

I hope it helps