Question

23] find the sum of an AP 5+8+11+-- to 10 terms using the
formula​

Answer 1

Answer:

185 is the correct answer.

Step-by-step explanation:

AP: 5, 8, 11, ...

Here,

First term a = 5

common difference d = 8-5 =3 & n = 10

$s10 \: = \: \frac{n{(2a + (n - 1)d)}}{2} \\ = \frac{10(2 \times 5 + (10 - 1)3)}{2} \\ = \frac{10(10 + 27)}{2} \\ = 5 \times 37 \\ = 185$