Question

Find the next two terms of the sequence: 80, −40, 20, −10, ______, ______.

A) 20, 40
B)
1
2
,
1
4
C) 5, −
5
2
D) −30, −40

Answer 1

5 and - 2.5

Explanation:

Note that consecutive terms have a common ratio, that is

- 40 ÷ 80 = 20 ÷ - 40 = - 10 ÷ 20 = - 0.5

This indicates that the sequence is geometric.

To find the next term in the sequence multiply the previous term by the common ratio, thus

- 10 × - 0.5 = 5

5 × - 0.5 = - 2.5