math algebra. i need help!?
A boat can travel 10 miles downstream in 70 minutes.The return trip upstream requires 2 hours. Find the rate of the boat and the rate of the current. PLEASE INCLUDE THE WORKING. THANK YOU!
- 1 decade agoFavorite Answer
Let v be the speed of the boat, c be the speed of the current.
Downstream (in the same direction): c + v = 10/70 = 1/7 miles/min.
Upstream (opposite directions): 10/(c - v) = 2 hrs = 120 min.
c - v = 10/120 = 1/12 miles/min
Summing both equations: 2c = 1/7 + 1/12 = 19/84
c = 19/168 miles/min = 0.113 miles/min = 6.79 miles/hr
v = 19/168 - 1/12 = 5/168 miles/min = 0.0298 miles/min = 1.79 miles/hr
- 1 decade ago
down stream(velocity of boat & water in same direction)
v+x=s/t; v is velocity of boat,x is of water,s is distance,t s time...
solving those two equations v=6.785miles/hr