document.write( "Question 315040: A water rocket is launched upward with an initial velocity of 48 ft/sec. It's height h, in feet, after t seconds is given by h=48t - 16t^2. After how many seconds will the height of the rocket be 20 feet? \n" ); document.write( "

Algebra.Com's Answer #225440 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+h=48t-16t%5E2=20\"$
\n" ); document.write( " $\"16t%5E2-48t%2B20=0\"$
\n" ); document.write( " $\"4t%5E2-12t%2B5=0\"$
\n" ); document.write( "Factor the quadratic.
\n" ); document.write( " $\"+%282t-5%29%282t-1%29=0+\"$
\n" ); document.write( "Two solutions:
\n" ); document.write( " $\"2t-5=0\"$
\n" ); document.write( " $\"2t=5\"$
\n" ); document.write( " $\"t=5%2F2\"$
\n" ); document.write( ".
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\n" ); document.write( ".
\n" ); document.write( " $\"2t-1=0\"$
\n" ); document.write( " $\"2t=1\"$
\n" ); document.write( " $\"t=1%2F2\"$
\n" ); document.write( ".
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\n" ); document.write( ".
\n" ); document.write( "The rocket first reaches 20 ft in 1/2 sec going up and then reaches 20 ft in 5/2 sec going down. \n" ); document.write( "

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