Question 761684
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 10 mph because of fog.  The total time for the trip is 6 h.  How far is the island from the harbor?
-------------
Avg speed for the round trip is
2*20*10/(20+10) = 40/3 mi/hr
---
d = r*t = (40/3)*6 = 80 miles RT
40 miles each way