# If the first term of an A.P is -18 and its last term is 108, find the sum of 30 terms of the given A.P.

Solution
Given, a = first term = - 18
= last term = 108
n = 30
As, we know that,
S$\frac{n}{2}\left(a+l\right)$
${S}_{30}=\frac{30}{2}\left(-18+108\right)=15×90=1350$

• 0
What are you looking for?