Question

Find the sum of the first 20 terms of an arithmetic series if the first term is 4 and the common difference is 3.

Answer 1

The sum of first 20 terms of Arithmetic Series is 650 if the first term is 4 and the common difference is 3.

Step-by-step explanation:

First Term  (a) = 4

Common difference  (d) = 3

The number of term (n) = 20

The sum of an Arithmetic series of (n) number of terms, with first term (a) and the common difference (d) is equal to

Sum =  (n/2) * ( 2 * a + (n -1) * d)

So putting the values of a,d, n

Sum = ( 20/2) * ( 2 * 4 + (20 -1) *3 )

Sum =  (10) * ( 8 + 19 * 3)

Sum =  10 * ( 8 + 57)

Sum = 10 * 65 = 650

Hence the sum of first 20 terms of Arithmetic Series is 650 if the first term is 4 and the common difference is 3.