Answer:
0.11 feet
Step-by-step explanation:
Every bounce, the ball bounces to 75% of its previous bounce, so the first few bounces will give us heights of
20 ft (0 bounces)
20 × 0.75 = 15 ft (1 bounce)
20 × 0.75 × 0.75 = 11.25 ft (2 bounces)
We can express the continued multiplication by 0.75 as an exponent, so that after the nth bounce, the ball will bounce [tex]20(0.75)^{n}[/tex] feet. Plugging in 18 for n gets us
[tex]20(0.75)^{18}\approx 0.11[/tex] feet.
