Question

Given an =3,n=8,sn = 192. find the value of d​

Answer 1

$\bold{Correct\: Question\::}$

Given a =3,n=8,sn = 192. find the value of d

Solution:

a = 3

n = 8

$S_{n}$ = 192

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• We have to find the value of d.

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* $S_{n}$ = $\dfrac{n}{2}$ (a + an)

Put the known values in above equation

$\implies$ $S_{8}$ = $\dfrac{8}{2}$ [2a + (n - 1)d]

$\implies$ 192 = 4[2(3) + (8 - 1)d]

$\implies$ 48 = 12 + 7d

$\implies$ 48 - 12 = 4d

$\implies$ 36 = 4d

$\implies$ d = 9

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$\huge{\bold{d\:=\:9}}$

___________ [ANSWER]