How would you find the tenth term?

Question

the 7th term of an arithmetic series is 21 and the 21st term is 301. What is the tenth term?

 

Answer 1

to advance from 7th to 21st term of an arithmetic sequence one must add the constant difference 14 times.

 

from 21 to 301 is advancement by 280, in total; thus d = 280/14 = 20.

 

Tenth term is 21 + 3(20) = 81.