<PRE><B>Question 393274</B>
An object is thrown up in the air at a velocity of 20 ft/sec. The height of the object t seconds after it is thrown is given by the function h(t)= -16t^(2)+20t . How long will it take for the object to hit the ground? 
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Height is zero when the object hits the ground.
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Solve: 
-16t^2+20t = 0
-4t(4t-5) = 0
Positive solution:
t = 5/4 = 1 1/4 seconds
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Cheers,
Stan H.</PRE>