SOLUTION: A van travels for two hours at an average speed of 40 miles per hour. For how long must the van then travel at an average speed of 55 miles per hour to raise the overall average sp

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A van travels for two hours at an average speed of 40 miles per hour. For how long must the van then travel at an average speed of 55 miles per hour to raise the overall average sp      Log On


   

Question 565011: A van travels for two hours at an average speed of 40 miles per hour. For how long must the van then travel at an average speed of 55 miles per hour to raise the overall average speed to 45 miles per hour? What is the total time traveled?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A van travels for two hours at an average speed of 40 miles per hour.
1st distance = 80 miles.
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For how long must the van then travel at an average speed of 55 miles per hour to raise the overall average speed to 45 miles per hour?
Let that time = x hrs;
Then distance traveled is 55x
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What is the total time traveled?
Final average = (total distance)/(total time) = (80+55x)/(2 + x)
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Equation:
45 = (80+55x)/(2+x)
90 + 45x = 80 + 55x
10x = 10
x = 1 hr. (time the van traveled at 55 mph)
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Cheers,
Stan H.
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