Posted by **lisa** on Tuesday, January 13, 2009 at 8:03pm.

the height that a ball bounces varies directly as the height from which it is dropped. A ball dropped from a height of 20cm bounces 16cm

a) Find the height of the bounce if the ball is dropped from a height of 280cm

b) Find from waht height the ball was dropped if it bounces to a height of 120cm

Thanks in advance.

- math -
**Reiny**, Tuesday, January 13, 2009 at 10:42pm
let h be the new height, let x be the height it was dropped from, then

h = kx, where k is a constant

when x=20, h=16

so 16=k20

k = 16/20 = 4/5

then h =4x/5

a)when x= 280

h = 4(280)/5 = 224

b) when h = 120

120 = 4x/5

600 = 4x

x = 150

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