SOLUTION: A car and a truck start at the same point and travel in opposite directions. The car travels 8 mi per hour faster than the truck. After 3 hours the car and the truck are 354 mi apa

Question 923757: A car and a truck start at the same point and travel in opposite directions. The car travels 8 mi per hour faster than the truck. After 3 hours the car and the truck are 354 mi apart. Find the average speed of the car and truck.
I did 3(x+8)=354. X+y=118
3y=354. y=118
But it makes no sense. Im trying to do it like ive been doing the upstream down stream but cant figure it out. Please help! Thank you!
Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A car and a truck start at the same point and travel in opposite directions. The car travels 8 mi per hour faster than the truck. After 3 hours the car and the truck are 354 mi apart. Find the average speed of the car and truck.
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Truck rate:: x mph
Car rate:::: x + 8 mph
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Equations::
Since they are traveling in opposite directions,
3(x + x+8) = 354 miles
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6x + 24 = 354
6x = 330
x = 55 mph (truck speed)
x+8 = 61 mph (car speed)
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Cheers,
Stan H.
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Answer by MathTherapy(10551) (Show Source): You can put this solution on YOUR website!

A car and a truck start at the same point and travel in opposite directions. The car travels 8 mi per hour faster than the truck. After 3 hours the car and the truck are 354 mi apart. Find the average speed of the car and truck.
I did 3(x+8)=354. X+y=118
3y=354. y=118
But it makes no sense. Im trying to do it like ive been doing the upstream down stream but cant figure it out. Please help! Thank you!

Let truck's speed be S
Then car's speed = S + 8
In 3 hours, truck has covered: (3S) miles
In 3 hours, car has traveled: 3(S + 8), or (3S + 24) miles
In 3 hours, both vehicles have traveled a total of 354 miles
Therefore, it can be said that: 3S + 3S + 24 = 354
Solve of S, the speed of the truck
Add 8 to truck's speed to get car's speed
You should get:
Truck's speed: mph
Car's speed: mph
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