document.write( "Question 920003: It takes a car 2 hour less time than a truck to travel a 400 mile distance. Find the rate if each vehicle if the car travels 10 mph faster than the truck.
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Algebra.Com's Answer #558100 by ewatrrr(24785) $\"\"$ $\"About$

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t = D/r
\n" ); document.write( "r the rate of the truck
\n" ); document.write( "400/r - 400/(r+10mph) = 2hr |Multiplying thru by r(r+10)so as all denominators = 1
\n" ); document.write( "400(r+10) - 400r = 2r(r+10)
\n" ); document.write( "2r^3 + 20r -4000 = 0
\n" ); document.write( "r^2 + 10r - 2000= 0 (Tossing out the negative solution for unit measure)
\n" ); document.write( "(r + 50)(r -40) = 0
\n" ); document.write( "r = $\"+highlight_green%2840mph%29\"$ , the rate of the truck. Car's rate is $\"+highlight_green%2850mph%29\"$ $\"40%2B10\"$
\n" ); document.write( "And...checking
\n" ); document.write( " $\"400mi%2F%2840mph%29+-+400mi%2F%2850mph%29\"$ = 10hr - 8hr = 2hr
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