Question

An ap consists of 31 terms. If 16th term is 10 find the sum of all the terms of this ap

Answer 1

Hope it helps..........
:)

Answer 2

Answer:

310

Step-bysad-step explanation:

No. of terms= n = 31

16th term = 10

Formula of nth term of AP = $a_n=a+(n-1)d$

Substitute n = 16

$a_{16}=a+(16-1)d$

$10=a+15d$  --A

Sum of n terms = $S_n=\frac{n}{2}(2a+(n-1)d)$

Substitute n = 31

$S_{31}=\frac{31}{2}(2a+(31-1)d)$

$S_{31}=\frac{31}{2}(2a+30d)$

$S_{31}=31(a+15d)$

Using A

$S_{31}=31(10)$

$S_{31}=310$

Hence  the sum of all the terms of this ap is 310