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A pleasure boat on the Mississippi River traveled from Baton Rouge to New Orleans
with a stop at White Castle. On the first part of the trip, the boat traveled
at an average speed of 10 mph. From White Castle to New Orleans the average speed
was 15 mph. The entire trip covered 100 miles. How long did the entire trip take
if the two parts each took the same number of hours?
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Let "d" be the unknown distance from Baton Rouge to White Castle.
Then the distance from White Castle to New Orleans is 100-d miles.
The travel time for the first part of the trip is hours.
The travel time for the second part of the trip is hours.
For these partial times we have this equation
= ,
according to the problem.
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| At this point, the setup is just complete. |
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To solve the equation, multiply both sides by 150. You will get
15d = 10*(100-d).
Simplify and find "d"
15d = 1000 - 10d
15d + 10d = 1000
25d = 1000
d = 1000/25 = 40.
So, the distance from Baton Rouge to White Castle is 40 miles;
the distance from White Castle to New Orleans is the rest 100-40 = 60 miles.
The total travel time is + = 4 + 4 = 8 hours. ANSWER
Solved.
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It can be solved in different way/ways, too;
but this way will give you the maximum understanding.