SOLUTION: The sum of the first 4 terms of geometric series is 15 and sum of the next four terms is 240. Determine the positive constant ratio.

Question 1065935: The sum of the first 4 terms of geometric series is 15 and sum of the next four terms is 240. Determine the positive constant ratio.
Answer by KMST(5328) (Show Source): You can put this solution on YOUR website!
= the first term
= the constant ratio
The sum of the first terms is
.
The sum of the next terms is
.
The ratio of the two sums is
,
which simplifies to
.
So, the positive constant ratio is .
No need to use the formula for sum of the first terms.
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