Question

In an AP AP if Sn = n(5n+ 2) then its 5th term is​

Answer 1

Given that

In an AP

Sn = n(5n+2)

SOLUTION

Sn = n(5n+2)

Put n= 1 to get first term of AP

A1 = 1(5×1 +2) = 7

Put n= 2 to get sum of first 2 term

S2 = 2 (5×2 + 2) = 24

Now the common different of AP

d = 24 - 7 = 17

Now the 5th term of AP

A5 = A1 + 4d = 7 + 17 × 4 = 75

Answer 2

Sn=n(5n+2)

5th term so n=5

=5((5*5)+2)
=5*27
=135