Question

what is the sum of the first 40 terms whose general term is An=5n+10

Answer 1

$A1 = 5×1 + 10 = 15,$

$A40 = 5×40 + 10 = 210.$

The sum of the first 40 terms is:

$S40 = 40×(15 + 210)/2 = 4,500.$