Choose the correct choice in the following and justify:
11th term of the AP: $-3, -\frac{1}{2},, 2, …,$ is
(A) 28
(B) 22
(C) $-38$
(D) $-48$

AcademicMathematicsNCERTClass 10

Given:

Given AP is $-3, -\frac{1}{2},, 2, …,$

To do:

We have to choose the correct choice.

Solution:

$a=-3$

$d=-\frac{1}{2}-(-3)=-\frac{1}{2}+3$

$=\frac{-1+6}{2}$

$=\frac{5}{2}$

$n=11$

We know that,

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

$a_{11}=-3+(11-1)(\frac{5}{2})$

$=-3+10(\frac{5}{2})$

$=-3+5(5)$

 $=-3+25$

$=22$

Hence, B is the correct choice. 

raja
Updated on 10-Oct-2022 13:20:19

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