SOLUTION: A ferry leaves a harbor and travels to a resort island at an average speed of 20 mph. On the return trip, the ferry travels at an average speed of 12 mph because of fog. The total

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Question 829657: A ferry leaves a harbor and travels to a resort island at an average speed of 20 mph. On the return trip, the ferry travels at an average speed of 12 mph because of fog. The total time for the trip is 5 h. How far is the island from the harbor?
Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
---
s = d/t
t = d/s
---
out:
t1 = D/20
---
return:
t2 = D/12
---
round-trip time:
t1 + t2 = 5
D/20 + D/12 = 5
12D/12*20 + 20D/12*20 = 5
12D + 20D = 5*12*20
32D = 5*12*20
D = 5*12*20/32
---
answer:
D = 37.5 miles
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