Question

there are 11 terms in A.p. the value of middle most term is 30. find sum of all terms of this A.p.​

Answer 1

Answer:

Using Formula - Sn = n/2 [2a + (n-1)d]

Step-by-step explanation:

Given :-

1. 11 terms in A.P.

2. Value of middle term = 30;

Middle most value of 11 is 6, Therefore, 6 th term is 30

6 th term can also be written as - a + 5d;

Therefore, a + 5d = 30, multiplying this equation by 2, we get 2a + 10d = 60;

Substituting values,nin the formula we get,

S11 = 11/2×[2a + 10d]

We already know the value of 2a + 10d as 60,

Therefore, we get S11 as, S11 = 11 × 30 = 330;

Hence the answer to this question is 330.

Thank You...! : )