SOLUTION: Going to the lake, has a mean speed of 12 mph. On the return trip the mean speed is 10 mph,. If the round trip takes 5.5 hrs., how long does the return trip take?

Question 1004142: Going to the lake, has a mean speed of 12 mph. On the return trip the mean speed is 10 mph,. If the round trip takes 5.5 hrs., how long does the return trip take?
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
The formula for distance is:
d= r*t where r is the rate (another word for speed) and t is time. Since we want to find t, let's divide both sides by rate:
t= d/r
----------
We have two speeds, so we have to add them up:
d/r+d/r= t Let's plug in the numbers in the problem:
d/12+d/10= 5.5 Now let's find a common denominator for 12 and 10: 12, 24, 36, 48, 60. Eureka!, 60 is divisible by 12 and by 10. Multiply all sides by 60:
60/12+60/10= 330 Simplify on left, divide:
60/12=5 and 60/10=6 Now we have:
5d+6d= 330
11d= 330 Divide by 11:
d= 30 This is the distance to the lake. And the return time is:
30/10= 3 hours
Proof:
30/10= 3
30/12= 2.5
Total: 3+2.5= 5.5 We have the correct answer.
RELATED QUESTIONS
Jane rides her bike to Lake Moultrie. Going to the lake she averages 12mph. On the return (answered by Alan3354)

Jane rides her bike to lake Junaluska. Going to the lake, she averages 12 mph. On the... (answered by ankor@dixie-net.com)

a man drove 5 hours. On the return trip his speed was 9 mph less and the trip took 6 hrs. (answered by jrb1965)

Marcus drives from one town to another in 6 hours. on the return trip, his speed is... (answered by nyc_function)

An airplane averages 150 mph. If a trip from Atlanta to Charleston takes 2 hours 48... (answered by math_tutor2020,greenestamps,josgarithmetic,ikleyn)

Ryan is rowing a small boat out to and back from an island 20 miles away at a rate of x... (answered by josgarithmetic)

During the first part of a trip, a canoeist travels 95 miles at a certain speed. The... (answered by richwmiller)

David travels for 6 hours at a rate of 50 mph. his return trip takes him 7.5 hrs. what is (answered by ankor@dixie-net.com)

A motorboat can go 18 mph in still water. If a trip downstream takes 4 hours and return... (answered by richwmiller)