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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 -

    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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