Question

Which term of the A.P. −29, −26, −23, ....., 61 is 16?

Options

• 11^th

• 16^th

• 10^th

• 31^th

Answer 1

16^th

Explanation:

Given

a = −29

d = −26 − (−29)

d = −26 + 29

d = 3

a_n = 16

Here we know

a_n = a + (n −1) d

⇒ 16 = −29 + (n − 1) 3

⇒ `(16 + 29)/3 = n − 1`

⇒ 15 = n − 1

∴ n = 16