# 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.

Given, a = first term = - 18

*l*= last term = 108

n = 30

As, we know that,

S

_{n }= $\frac{n}{2}\left(a+l\right)$

${S}_{30}=\frac{30}{2}\left(-18+108\right)=15\times 90=1350$

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