SOLUTION: The ratio of the sum of the first three terms of a G.P to the sum of the first 6 terms is 27:19.The common ratio is 2÷3 -2÷3 -1.5 1.5

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: The ratio of the sum of the first three terms of a G.P to the sum of the first 6 terms is 27:19.The common ratio is 2÷3 -2÷3 -1.5 1.5      Log On


   

Question 1133674: The ratio of the sum of the first three terms of a G.P to the sum of the first 6 terms is 27:19.The common ratio is
2÷3
-2÷3
-1.5
1.5
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


%28a%2Bar%2Bar%5E2%29%2F%28a%2Bar%2Bar%5E2%2Bar%5E3%2Bar%5E4%2Bar%5E5%29+=+27%2F19

The 4th, 5th, and 6th terms of the GP are each r^3 times the 1st, 2nd, and 3rd terms:

%28a%2Bar%2Bar%5E2%29%2F%28%28a%2Bar%2Bar%5E2%29%281%2Br%5E3%29%29+=+27%2F19

1%2F%281%2Br%5E3%29+=+27%2F19

27%281%2Br%5E3%29+=+19

27%2B27r%5E3+=+19

27r%5E3+=+-8

r+=+-2%2F3