Question

A geometric series has 8 terms whose sum of the first three terms is 7 and the sum of last three terms is 224.Find the first and the common ratio of this series​

Answer 1

Explanation:

Let the terms be a ar ar^2 ar^3 ……ar^7

Acq,

ar^5+ar^6+ar^7=224

r^5(a+ar+ar^2)=224

Since, sum of first 3 terms is 7

::r^5=224/7

::::r=2, a=1 ANSWER