Question

How many terms are there in the A.P.?

7, 10, 13, ... 43

Answer 1

In the given problem, we are given an A.P.

We need to find the number of terms present in it

So here we will find the value of n using the formula, `a_n = a + (n -1)d`

Here, A.P is  7, 10, 13, ... 43.

The first term (a) = 7

The last term `(a_n)` = 43

Now

Common difference (d) = `a_1 - a`

= 10 - 7

= 3

Thus, using the above mentioned formula, we get,

43 = 7 + (n - 1)3

43 - 7 = 3n - 3

36 + 3 = 3n

`n = 39/3`

n = 13

Thus, n = 13

Therefore, the number of terms present in the given A.P is 13