Question

Which term of the series is 635 if the first term is 15 and the common difference is 5​

Answer 1

Given:

an=635

First term (a1)= 15

Common difference (d)=5

To Find:

n=?

Solution:

an=a+(n-1)d

635=15+(n-1)5

635=15+5n-5

635=10+5n

635-10=5n

625=5n

5n=625

n=625/5

n=125