3. BACKBOARD
Ei liked to play tennis. One day she didn't have anyone to play with, so
she took her racket and tennis ball and began to hit the ball against the
backboard. She hit it at the backboard, the ball bounced off the
backboard and came back to her, and she hit it again, and so on. She
started out 40 feet from the backboard. But she didn't hit the ball hard
enough-the bounce came back only 90% as far, so she had to run up to
hit it again. Again she didn't hit it hard enough, and it again only came
back 90% as far as she had hit it. This continued for two more hits, each
time the ball coming back 90% as far. Finally on the fifth hit she hit it
really hard and it came back five times as far as she had hit it, going way
over her head and hitting the fence. She got frustrated, and picked up her
ball and went home. How far was the distance from the backboard to the
fence? What was the total horizontal distance that the tennis ball traveled?