What is the sum of the first 12 terms of an arithmetic progression if the first term is -19 and last term is 36?

Solution (By Examveda Team)

First term of AP = a = -19 and last term = l = 36
Number of terms = n = 12
$$\eqalign{ & {\text{Sum of AP}} = \frac{n}{2}\left( {a + l} \right) \cr & = \frac{{12}}{2}\left( { - 19 + 36} \right) \cr & = 17 \times 6 \cr & = 102 \cr} $$