SOLUTION: S is an arithmetic series. S12 = 150 S25 = 875 What is the value of S40? Round to 2 decimal places.

Question 1161258: S is an arithmetic series.
S12 = 150
S25 = 875
What is the value of S40? Round to 2 decimal places.
Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!

is an arithmetic series.
so, nth term formula is:

if , we have

.......solve for
......eq.1

if , we have

.....solve for
......eq.2
from eq.1 and eq.2 we have
...solve for

go to
......eq.1, substitute

your formula is:

then, the value of is:

....round to decimal places

Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

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