Question

If the first term in an arithmetic sequence is 15 and the tenth term is 69. What is the fourth term in the sequence?

Answer 1

Hello,


`a_(0)=15` first term

`a_(1)=15+r` second term

`a_(2)=15+2r` third term
...

`a_(9)=15+9r` is the tenth term =69

15+9r=69
==>9r=69-15
==>r=54/9=6

`a_(3)=15+3r=15+18=33`