Question

If the sum of n terms of an AP is 3n2 + 5n, then which of its term is 164?

Answer 1

Hy

Given
Sn=3n sq + 5n

Now Tn= Sn-Sn-1

= 3nsq +5n- 3(n-1)sq -5(n-1)

= 3(nsq - nsq -1 +2n)+5 (n-n+1)

= 6n -3 + 5
= 6n +2

Now given tn= 164

6n+2=164

6n= 162
n= 27 Ans

Hope it hells...

Answer 2

Hello...

Here is your solution...

Hope this will help you...

Thank you so much.....