Question

7th term of an ap i 40 then the sum of first 13 terms

Answer 1

Answer:

the 7 th term of ap its t7 which is 40

t7 = a +(n-1)d

hence,40 =a+6d

s13=13/2(2a+(n-1)d)

=13/2×2(a+6d)

=13× 40

=520