Question

find the sum of first 30 terms of an AP 5,8,11 up-to 30 terms using formula​

Answer 1

Answer:

3*30-2

=88

30/2*5+88

= 15*92

1,380

Answer 2

Answer:

1455

Step-by-step explanation:

We have,

first term(a)=5

common difference (d) =8-5=11-8=3

Now,

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

S30=30/2 [2*5 + (30-1)3]

=15 [10+87]

=15*97

=1455