Question

The 11^th term of the AP: `-5, (-5)/2, 0, 5/2, ...` is ______.

Options

• –20

• 20

• –30

• 30

Answer 1

The 11^th term of the AP: `-5, (-5)/2, 0, 5/2, ...` is 20.

Explanation:

First term, a = – 5

Common difference,

d = `5 - ((-5)/2)`

= `-5/2 + 5`

= `(-5 + 10)/2`

= `5/2`

n = 11

We know that the n^th term of an AP is

a_n = a + (n – 1)d

Where,

a = first term

a_n is n^th term

d is the common difference

a₁₁ = `-5 + (11 - 1)(5/2)`

a₁₁ = `-5 + (10)(5/2)`

a₁₁ = – 5 + 5(5)

a₁₁ = – 5 + 25

a₁₁ = 20