Question

Choose the correct choice in the following and justify:

11^th term of the A.P. `-3, -1/2, 2,` ..., is ______.

Options

• 28

• 22

• –38

• – 48`1/2`

Answer 1

11^th term of the A.P. `-3, -1/2, 2,` ..., is 22.

Explanation:

Given that A.P. is -`3, -1/2, 2, ...`

First term a = -3

Common difference, d = a₂ − a₁ = `(-1/2) - (-3)`

= `(-1/2) + 3`

= `5/2`

We know that, a_n = a + (n − 1) d

a₁₁ = `3 + (11 -1)(5/2)`

a₁₁ = `3 + (10)(5/2)`

a₁₁ = -3 + 25

a₁₁ = 22

Hence, the answer is 22.