Question

in a geometric progression,the 7th term is 16 times the 3rd term and the sum of the 2nd and the 6th term is 102.if the common ratio r is positive.Find (a)r
(b)the first term
(c)S₈-S₄

Answer 1

Step-by-step explanation:

Let me quickly dive into this one; quite elementary.

For third term



For sixth term









By putting r in one of the equations above





Now, given that the values of first term a and common ratio r are known,let’s plug in values

For the seventh term given by sixth term times common ratio r





Very important to remember:



is the common ratio between sixth and third term.

That is it! Simple and clear.