Question 1199441
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When a ball is thrown upward, its height, h meters, is given by h=1.5+19.6t-4.9t2, 
where t seconds is the time after it is thrown. 
For what length of time is the ball higher than 16.2m?
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<pre>
To answer the question, you need to solve this inequality

    1.5 + 19.6t - 4.9t^2 > 16.2.


Transform it to an equivalent inequality

    4.9t^2 - 19.6t + 14.7 < 0


Divide both sides by 4.9

    t^2 - 4t + 3 < 0.


Factor left side

    (t-3)*(t-1) < 0


The solution set is  1 < t < 3.


The ball will be above  16.2 m  for  3 - 1 = 2 seconds.    <U>ANSWER</U>
</pre>

Solved.