SOLUTION: 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

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Question 1119092: 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?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
                  SPEED         TIME           DISTANCE
CAR               r+30          540/(r+30)       540
TRUCK              r            540/r            540
DIFFERENCE                       3


Truck's time is larger than the car's time.
540%2Fr-540%2F%28r%2B30%29=3-------simplify and solve this for r.
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180%2Fr-180%2F%28r%2B30%29=1
.
.
r%5E2%2B30r-5400=0

r=%28-30%2Bsqrt%2822500%29%29%2F2

highlight%28r=60%29------truck speed

r%2B30=highlight%2890%29------car speed