<PRE><B>Question 890265</B>
A car travels 30 kph faster than a truck. The car covers 540 km in three hours less than the time it takes the truck to travel the same distance. What is the speed of the car? What about the truck?
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let x=speed of truck
x+30=speed of car
travel time=distance/speed
{{{540/x-540/(x+30)=3}}}
lcd:x(x+30)
540x-540(x+30)=3x(x+30)
540x-540x-16200=3x^2+90x
3x^2+90x-16200=0
x^2+30x+5400=0
(x+90)(x-60)=0
x=-90 (reject)
or
x=60
x+30=90
speed of truck=60 km/hr
speed of car=90 km/hr

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