An arithmetic series contains 20 numbers. The first number is 102. The last number is 159. Which expression represents the sum of the series?

A. (20 (159-102/2)

B. (20 (102+159/2)

C. 20 (102+159)

D. 20 (159-102)

Option B

Step-by-step explanation:

we know that

The sum of an arithmetic series is equal to

S=n (a1+an) / 2

where

a1 is the first term

an is the last term

n is the number of terms

In this problem we have

n=20

a1=102

an=159

substitute the values in the formula

S=20 (102+159) / 2