OK I'm really bad at this stuff if you can help me I would totally appreciate it.
an excursion boat takes 1.5 times as long to go 360 miles up a river than to return. if the boat cruises at 15 mph in still water, what is the rate of the current?
2006-12-03 16:03:20 · 4 answers · asked by Penny C 1 in Science & Mathematics ➔ Mathematics
Ok, here's the real answer...
The key is this:
let x = rate of the current (in mph)
then 15 + x = speed of boat going downriver
15 - x = speed of boat going upriver
The problem says that 1.5 * (time to go downriver) = (time to go upriver)
So 1.5 * (1 / (15 + x)) = (1 / (15 - x))
Rearrange that to get:
(15 + x) / (15 - x) = 3 / 2
Solve for x, and you find that x = 3.
The current is 3 mph
2006-12-03 16:30:08 · answer #1 · answered by Bill C 4 · 0⤊ 0⤋
Given the parameters of the question, if the boat travels at 15 mph in one direction, it would travel at 10 mph or 22.5 mph in the other direction.... However, if the boat is in still water, there would be no current present in either situation; the speed of the boat would have to be attributed to some other factor... possibly a change of time zones, if no change in velocity (mph) is made.
2006-12-04 00:16:52 · answer #2 · answered by J D 2 · 0⤊ 0⤋
Does still water have a current?
2006-12-04 00:05:47 · answer #3 · answered by Meridianhawk42 3 · 0⤊ 0⤋
It`s 18mp/h
2006-12-04 05:11:36 · answer #4 · answered by Anonymous · 0⤊ 0⤋