# What is the 30th term of the arithmetic series 11+16+21+26+...?

Jun 8, 2016

${T}_{30} = 11 + 145 = 156$

#### Explanation:

It can easily be seen that the common difference between the terms is 5. The first term, a, is 11

The general term is $T n = a + \left(n - 1\right) d$
For this series is ${T}_{n} = 11 + \left(n - 1\right) 5$

So for${T}_{30} = 11 + 29 \times 5$

= $11 + 145 = 156$