Question

in an AP given a=3 , n=8 , s=192 find d

Answer 1

given=>S=192
a=3
n=8
d=?
since ,S=n/2[2a+(n-1)d]
192=8/2[2×3+(8-1)d]
192=4[6+7d]
192/4= 6+7d
48=6+7d
48-6=7d
42=7d
42/7=d
6=d

Answer 2

Answer:

The common difference is d=6

Step-by-step explanation:

Given : In an AP given a=3 , n=8 , s=192

To find : The common difference d

Solution :

The formula of sum of the A.P is

$S_n=\frac{n}{2}[2a+(n-1)d]$

Substitute, a=3 , n=8 , s=192

$192=\frac{8}{2}[2(3)+(8-1)d]$

$192=4[6+7d]$

$192=24+28d$

$192-24=28d$

$168=28d$

$\frac{168}{28}=d$

$d=6$

Therefore, The common difference is d=6