Question

What is the nth term of this number sequence 25, 20, 15, 10, 5
Please answer it

Answer 1

`a_(n)` = 30 - 5n

Explanation:

There is a common difference between consecutive terms, that is

20 - 25 = 15 - 20 = 15 - 20 = 10 - 15 = 5 - 10 = - 5

This indicates the sequence is arithmetic with n th term

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = 25 and d = - 5, thus

`a_(n)` = 25 - 5(n - 1)

= 25 - 5n + 5

= 30 - 5n