The sum of the first and third terms of a geometric progression is 40 while the fourth and sixth term are in the ratio 1:4 . Find the common ratio and fifth term
4th term is 1 out of (4+1) = 1/5 sixth term is 4/5
1/5 x r x r = 4/5
r^2 = 4 r =2
1st and third terms x + x * r * r = 40
x + 4x = 40
x = 8 = first term
5th term 8 r^4 = 8 * 16 = 128