Answers

2016-02-22T21:28:48+05:30
Given
5th term=80=a.r^4
6th term=640=a.r^7
…a.r^7=640
a.r^4.r^3=640
80.r^3=640
r^3=8
r=2
g.p. Series are
5,10,20,40,80,160,320,640……………
1 5 1