Question

What is the sum of the first 10 terms of an AP whose n th term is given by - 3 + 4 n ?

Answer 1

Answer

The sum of 10th term of an AP = 215

Step-by-step explanation:

Given,

= 3n + 5

To find, the sum of first 10 terms of an AP = ?

Put n = 1, 2, 3, 4,  ......

Put n = 1

= 3(1) + 5 = 3 + 5 = 8

Put n = 2

= 3(2) + 5 = 6 + 5 = 11

Put n = 3

= 3(3) + 5 = 9 + 5 = 14

Here, first term(a) = 8, common difference(d) = 11 - 8 = 3 and

the number of term(n) = 10

We know that,

The sum of nth term of an AP,

The sum of 10th term of an ap= 5 × 43 = 215

Thus, the sum of 10th term of an AP = 215