SOLUTION: a ball is dropped from a height of 30 feet.each time it strikes the ground, it bounces up to 4/5 of the previous height. how many times does the ball hit the ground before it bounc

Question 1043565: a ball is dropped from a height of 30 feet.each time it strikes the ground, it bounces up to 4/5 of the previous height. how many times does the ball hit the ground before it bounces up less than 6 feet?
Found 2 solutions by ikleyn, MathTherapy:
Answer by ikleyn(52794)   (Show Source): You can put this solution on YOUR website!
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a ball is dropped from a height of 30 feet.each time it strikes the ground, it bounces up to 4/5 of the previous height.
How many times does the ball hit the ground before it bounces up less than 6 feet?
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# of hit/bounce height of bouncing 0 30.00 1 24.00 2 19.20 3 15.36 4 12.29 5 9.83 6 7.86 7 6.29 8 5.03 9 4.03 Geom. progression. = 30, common ratio r = . = , n = 1, 2, 3, . . . height after n-th bounce. Your n is 7.

On geometric progressions, read the lesson
    - Geometric progressions
in this site.

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!
a ball is dropped from a height of 30 feet.each time it strikes the ground, it bounces up to 4/5 of the previous height. how many times does the ball hit the ground before it bounces up less than 6 feet?

This situation depicts a sequence with being 30, r being , and being 5 (< 6).
We then have:

_____

n, or number of bounces = 8.029626932, or
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