Question

In the following APs, find the missing term in the box:

`5, square, square, 9 1/2`

Answer 1

`5, bb(6 1/2, 8), 9 1/2`

Explanation:

For this A.P.,

a = 5 and

a₄ = `9 1/2`

We know that, an = a + (n − 1) d

⇒ `9 1/2 = 5 + (4 - 1) ("d")`

⇒ `9 1/2 = 5 + 3"d"`

⇒ `3d = 9 1/2 - 5`

= `4 1/2`

⇒ `"d" = 13 × 4 1/2`

= `1 1/2`

⇒ `"a"_2 = 5 + 1 1/2`

= `6 1/2`

a₃ = 5 + 2 × `1 1/2`

= 5 + 3

= 8

Therefore, the missing terms are `6 1/2` and 8 respectively.