Question

A1=7 and d=4 find S20

Answer 1

83

Explanation:

S20 = a + ( n - 1) d

S20 = 7 + ( 20 - 1) 4

S20 = 7 + (19) 4

S20 = 7 + 76

S20 = 83.

Answer 2

Explanation:

w we will use the formula for finding sum up to a particular term i.e.. n[2a+(n-1)d]/2. n=20, d=3,a=1. using the formula we get the answer - 590.

Hope that helps :D.