Question

What is the sum of the first 17 terms of an AP if the first term is -20 and last term is 28?​

Answer 1

Answer:

68

Step-by-step explanation:

S=n/2 (a+l)

here n=17

        a= -20

         l=28

s = 17/2 ( -20 + 28 ) {which is (28 -20) }

s = 17/2 * 8

s = 17*4

s = 68