SOLUTION: Bob is making a 40-kilometer boat trip. if he travels at 30 kilometers per hour for the first 10 kilometers, and then at 15 kilometers per hour for the rest of the trip, how many m
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Question 212115: Bob is making a 40-kilometer boat trip. if he travels at 30 kilometers per hour for the first 10 kilometers, and then at 15 kilometers per hour for the rest of the trip, how many minutes more will it take him than if he tarvels the entire trip at 20 kilometers per hour?
Answer by drj(1380) (Show Source): You can put this solution on YOUR website!
Bob is making a 40-kilometer boat trip. If he travels at 30 kilometers per hour for the first 10 kilometers, and then at 15 kilometers per hour for the rest of the trip, how many minutes more will it take him than if he travels the entire trip at 20 kilometers per hour?
Step 1. Translate following into an equation: He travels at 30 kilometers per hour for the first 10 kilometers. We note that
Distance=Velocity*Time
hours
minutes where 60 minutes = 1 hours
minutes
where Distance = 10 km, x is the time he travels at 30 kilometers per hours and 30x is the distance traveled.
Step 2. 15 kilometers per hour for the rest of the trip which in this case is 10 kilometers = 40-30.
hours
minutes
minutes
Step 3. Add Step 1 and Step 2 for Total Time.
Total time = 20 minutes + 40 minutes = 60 minutes = 1 hour
Step 4. Last part of the problem means he travels 40 km at 20 kilometers per hour.
hour
hour
minutes
minutes
where z is the amount of time for this part of the problem.
Step 5. The amount of time in Step 3 is 60 minutes and amount of time in Step 4 is 30 minutes. So Step 3 is 30 minutes more than Step 4.
For more Step-By-Step Videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra.
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