Question

in an A. P it is given that a=3,n=8 and sn.192 then the value of d​

Answer 1

$\huge \mathfrak{given}$

• a = 3

• n= 8

and

• Sn= 192

TO FIND :

• The value of d.

$\huge \mathfrak{solution}$

As we know that ,

$\star \bold{s_n = \frac{n}{2} (2a + (n - 1)d})$

put the given values :

$\implies \: 192 = \frac{8}{2} (2(3) + (8 - 1)d) \\ \\ \implies \: 192 = 4(6 + 7d) \\ \\ \implies \: \frac{192}{4} = 6 + 7d \\ \\ \implies \: 48 = 6 + 7d \\ \\ \implies \: 48 - 6 = 7d \\ \\ \implies \: d = \frac{42}{7} \\ \\ \implies \: d = 6$

Hence , the value of d is 6 .

Answer 2

Answer:

Value of d = 6

Explaination

Given -

• a= 3
• n= 8
• sn= 192

To Find -

• Value of D

Solution -

Using formula - Sn= n/2 ( 2a+( n-1)d)

Putting value -

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

Hence, the value of d = 6

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