Question

In the A.P. 8, 13, 18, ........., the nth term is 83, then n is equal to ______.

Options

• 14

• 16

• 13

• 15

Answer 1

In the A.P. 8, 13, 18, ........., the nth term is 83, then n is equal to 16.

Explanation:

Let a be the first term and d be the common difference between provided A.P.

Here a = 8; d = 13 – 8 = 5

Given T_n = 83

`\implies` a + (n – 1)d = 83

`\implies` 8 + (n – 1)5 = 83

`\implies` (n – 1)5 = 83 – 8 = 75

`\implies n - 1 = 75/5 = 15`

`\implies` n = 15 + 1 = 16