This is a pretty tricky question...been trying to piece it together but I think I need some help. A ball is dropped from a height of 3 m. After each bounce, it rises to 82% of its previous height. After how many bounces does the ball reach a height less than 15cm? I get the whole geometric series thing, finding 'n' and all that, but what's with the "less than 15cm"? What do I do in this case?