Find the sum of the following arithmetic series 7+13+19+25+...+85

Step-by-step explanation:

Given Arithmetic series is:

7+13+19+25+...+ 85

Here,

First term a = 7

Common Difference d = 13 - 7 = 6

last term

First let us find the number of terms in given series.

Hence, given series has total 14 terms.

Sum of n terms of an Arithmetic series is given as:

answer: 42

use a calculator to find that 845/73 = 11.575

the whole part of the answer is 11. multiply this by 73 to get 11*73 = 803.

subtract that result from 845 to get 845 - 803 = 42