Question

If the common differences of an Ap is 5, the value of a18-a13 is

Answer 1

25

Explanation:

The n th term of an AP is

`a_(n)` = a₁ + (n- 1)d

where a₁ is the first term and d the common difference

Here d = 5, then

a₁₈ = a₁ + 17d = a₁ + 85

a₁₃ = a₁ + 12d = a₁ + 60

Thus

a₁₈ - a₁₃

= a₁ + 85 - a₁ - 60

= 25