Question 849451: two vehicles are 720 miles apart. at the same, they begin traveling toward each other. one vehicle is traveling 20 mph faster than the other. after traveling for four hours,the vehicles are 240 miles apart. what is the speed of each vehicle?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! the cars are 720 miles apart.
after traveling for 4 hours, the cars are now 240 miles apart.
this means the cars have traveled a total distance of 480 miles, because 720 - 240 is equal to 480.
The first car is traveling at a rate of R miles per hour.
The second car is traveling at a rate of R + 20 miles per hour.
The formula used is R * T = D
This translates to rate * time = distance.
the rate is given as R and R + 20
The time is given as 4 hours.
The distance is determined by the formula.
For the First car, the formula becomes 4R = D1
For the second car, the formula becomes 4(R + 20) = D2
Simplify these formulas and you get:
4R = D1
4R + 80 = D2
D1 and D2 must be equal to 480, so you get the formula of:
D1 + D2 = 480
Since D1 = 4R and D2 = 4R + 80, then replacing D1 and D2 in the formula gets:
4R + 4R + 80 = 480
solve for R to get R = 50
this means that R + 20 = 70
the cars are traveling at 50 miles per hour and 70 miles per hour.
in 4 hours,the slower car has traveled 200 miles.
in 4 hours, the faster car has traveled 280 miles.
add them up and you get 480 miles that both cars have traveled.
720 - 480 = 240 which means that the cars are now 240 miles apart after the 4 hours is up.
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