Find S10 for 2 + 5 + 8 +...

Question

A. 155
B. 152
C. 255
D. 135
I say A.

Answer 1

You have an arithmetic series where
a = 2, d = 3, n = 10

sum(10) = (10/2)(4 + 9(3)) = 5(31) = 155

looks like you are right.