Question

Stumped again .. A ball was dropped and measured rebound heights (in ft.) after each bounce. It was found that the rule y= 15(0.80^x) could be used to predict the rebound height of the ball, where y is the bounce height and x is the bounce number.

From what initial height did they drop the ball?
I come up with two different answers, 12 and 15 .. not sure which is correct, if either is even correct. ... i multiplied by 15 X .8 = 12 .. would this be correct?

Next, how do i figure how the rebound height changes from one bounce to the next?

Thanks again, in advance. - English is my forte`; obviously NOT algebra! lol