SOLUTION: A bus is traveling 15 mph slower than an 18 wheeler. In the time it takes the bus to travel 190 miles, the 18-wheeler travels 135 miles. Find the speed of both the bus and the 18-w

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A bus is traveling 15 mph slower than an 18 wheeler. In the time it takes the bus to travel 190 miles, the 18-wheeler travels 135 miles. Find the speed of both the bus and the 18-w      Log On

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Question 818988: A bus is traveling 15 mph slower than an 18 wheeler. In the time it takes the bus to travel 190 miles, the 18-wheeler travels 135 miles. Find the speed of both the bus and the 18-wheeler.
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Speed of truck is r.

__________________speed_____________time____________distance
Bus_______________r-15______________(___)___________190
Truck_____________r_________________(___)___________135

We need time expressions for the equal time of both bus and truck:

__________________speed_____________time____________distance
Bus_______________r-15______________190/(r-15)___________190
Truck_____________r_________________135/r___________135

You should already sense a mistake in the given information. Equal time, the bus is slower but traveled more miles than the truck. This cannot be. You mixed-up some information.

190%2F%28r-15%29=135%2Fr
LCD r(r-15)
or
135%28r-15%29=190r
135r-135%2A15=190r
135r-190r=135%2A15
-55r=135%2A3%2A5
r=-%28135%2A3%2A5%29%2F%2811%2A5%29=-135%2A3%2F11

Why should we allow r%3C0?