document.write( "Question 1113901: Tommy and Zach are starting out at the same position. Tommy runs north at 3 miles per hour and Zach starts to run east 2 hours later at the rate of 4 miles per hour. How long until Tommy and Zach are 8 miles apart?\r
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Algebra.Com's Answer #728954 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "The distance between them is the hypotenuse of a right-angled triangle with the legs of  3t miles  and  4(t-2) miles:\r\n" );
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document.write( "D = .\r\n" );
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document.write( "The problem asks to find \"t\" such as\r\n" );
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document.write( " = 8,   or,  equivalently,  9t^2 + 16*(t-2)^2 = 64.\r\n" );
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document.write( "9t^2 + 16t^2 - 64t + 64 = 64\r\n" );
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document.write( "25t^2 = 64t   ====>  the only answer is  t = 64/25 of an hour  after Tommy started his run,  or  0.56 of an hour = 33.6 minutes  after Zach  started his run.\r\n" );
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