You can put this solution on YOUR website! rays boat can go 20 mph in still water.
how far downstream can ray go if the current is 5mph and he wishes to go down and back in 4 hours.
:
20 + 5 = 25 mph effective speed downstream
20 - 5 = 15 mph effective speed up stream
:
let d = the one-way distance
:
Write a time equation; time = dist/speed
:
time downstr + time upstr = 4 hrs + = 4
multiply by the least common multiple of 25 and 15; 75,resulting in:
3d + 5d = 75(4)
8d = 300
d = 300/8
d = 37.5 mi downstream, then return
:
:
Confirm this, find the actual time each way
37.5/25 = 1.5 hrs
37.5/15 = 2.5 hrs
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total time: 4 hrs
