SOLUTION: One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upstream. How fast is the current in mph? (Round your an

Question 729047: One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upstream. How fast is the current in mph? (Round your answer to the nearest tenth of miles per hour and enter only the numerical part.)
Answer by checkley79(3341) (Show Source): You can put this solution on YOUR website!
D=RT
47=(15+C)T
40=(20-C)T
------------------
87=35T
T=87/35
T=2.5 HOURS.
47=(15+C)2.5
47=37.5+2.5C
2.5C=47-37.5
2.5C=9.5
C=9.5/2.5
C=3.8 MPH. IS THE CURRENT SPEED.
PROOF:
40=(20-3.8)2.5
40=16.2*2.5
40=40
RELATED QUESTIONS
One boat travelling 15 mph goes 36 miles downstream in the same amount of time that... (answered by lwsshak3)

One boat travelling 15 mph goes 36 miles downstream in the same amount of time that... (answered by ankor@dixie-net.com)

One plane travelling 380 mph goes 1389 miles with the wind in the same amount of time... (answered by ikleyn)

One Plane traveling 400 mph goes 1,250 miles with the wind in the same amount of time... (answered by 55305)

Connie McNair's boat goes 12 mph. Find the rate of the current of the river if she can go (answered by solver91311)

Kellen�s boat goes 12 mph. Find the rate of the current of the river if she can go 6 mi... (answered by scott8148)

On plane travelling 350 mph goes 1200 miles with the wind in the same amount of time that (answered by richwmiller)

The current in a stream is 2 mph. Find the speed of the boat in still water if it goes 26 (answered by stanbon)

a boat goes 7 mph in still water. It takes as long to go 20 mi upstream AS 50 mi... (answered by mananth)