Question

In the series (6,11,16,21), what is the 20th term?

Answer 1

as you can see the difference between each term is 5 , so this is an arithmetic series

Answer 2

using the formula

\[a_n=a_1+(n-1)d\]

where a1=6,n=20, and d =5 you get

\[a_20=6+(20-1)5\]

Answer 3

\[a_{20}=6+(19)(5)\]