Question

Find the sum of the first 38 terms of the arithmetic sequence:
3, 8, 13, 18, 23, ...


A)
Sn= 988


B)
Sn= 1010


C)
Sn= 3283


D)
Sn= 3629

Answer 1

help

Answer 2

it is a AS with d=5 a=3
therefore the general term = a +d(n-1) = 3+5(n-1) = 5n-2
the 38term = 5(38)-2 = 188
sum of first 38 terms = (a+l)n/2 = (3+188)x38/2 = 3629