Question

What is the twentieth term of the arithmetic sequence described by the
equation an= 3n - 10?

Answer 1

The twentieth term is 50.

Explanation:

The equation that describes the arithmetic sequence describes it's "general term", which means that all the numbers in that sequence must follow that equation. For instance, if we want to find the first term of the sequence we must make a = 1 and we have:

a1 = 3*1 - 10

a1 = -7

Therefore to find the twentieth term we need to make n equal to 20. This is done below:

a20 = 3*20 - 10

a20 = 60 - 10

a20 = 50

The twentieth term is 50.