Okay, There are a few on my homework that i don't understand...

A ball drops from a height of 19 feet. Each time it hits the ground, it bounces up 40 percents of the height it fall. Assume it goes on forever, find the total distance it travels.

i wrote this as a geometric series, with sigma(from n=1 to infinity) of 19*0.4^(n-1), which would then converge to a/1-r = 31.6666, but it's incorrect, is there an error in the way i set it up?

Determine the sum of: sigma(from n=1 to infinity) of (4^(n-1)/8^n)

not sure how to do this!

Also need help with from n=5 to infinity of 7^n/8^n and from n=1 to infinity of (7^n+2^n)/(8^n)