Question

How many terms are there in the following AP?
7, 10, 13, …, 43

• A. 12
• B. 14
• C. 16
• D. 13

Answer 1

The correct option is D 13

Here
First term, a = 7
Common difference, d = 10 - 7 = 3

Using the formula for $n^{th}$ term
$a_n=a+(n-1)d$
$43=7+(n-1)3$
$36=(n-1)3$
$12=n-1$
$n=13$
There are total 13 terms in the given AP.