SOLUTION: What is Sn for the arithmetic series with d=-4, an=27, and n=9 a.360 b.387 c.418 d.451

Algebra ->  Sequences-and-series -> SOLUTION: What is Sn for the arithmetic series with d=-4, an=27, and n=9 a.360 b.387 c.418 d.451      Log On


   

Question 742611: What is Sn for the arithmetic series with d=-4, an=27, and n=9
a.360
b.387
c.418
d.451
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Sn= n/2[2a+(n-1)d]
=>9/2[54+32]
=>387