SOLUTION: What is the sum of the finite arithmetic series? (-5)+0+5+10+...+65 a. 900 b. 455 c. 450 d. 445

Algebra ->  Sequences-and-series -> SOLUTION: What is the sum of the finite arithmetic series? (-5)+0+5+10+...+65 a. 900 b. 455 c. 450 d. 445      Log On


   

Question 853273: What is the sum of the finite arithmetic series?
(-5)+0+5+10+...+65
a. 900
b. 455
c. 450
d. 445
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
65 = -5 + (n - 1)5
n=15
S = ½(-5 + 65)15=450
also
S = ½(2a + d(n-1))n
S = ½(-10 + 5(14))15
S=1/2(60)15=450
c. 450