Math
posted by Analica .
A boat travels 45 miles upstream in 5h. The boat travels the same distance downstream in 3hr. What is the rate of the boat in still water? What is the rate of the current? (thank you)

stillwater speed: s
river speed: r
45 = 5(sr) = 3(s+r)
5s  5r = 45
3s + 3r = 45
multiply to match coefficients of r:
15s15r=135
15s+15r=225
30s = 360
s=12
r=3
check:
45mi/9mph = 5 hr
45mi/15mph = 3 hr
Respond to this Question
Similar Questions

word problem
A motor boat took 4 hours to make a downstream trip with a current of 3mph. The return trip against the same current took 8 hours. Find the speed of the boat in still water. Call Y the boat's rate. distance = rate x time. downstream … 
Intermediate Algebra Word Problem
A river's current is 4mph. A boat travels 48 miles downstream in the same time it travels 24 miles upstream. Find the speed of the boat. A) What does the variable stand for? 
Algebra 2
The excursion boat on the river takes 2½ hours to make the trip to a point 12 miles upstream and to return. If the rate at which the boat travels in still water is 5 times the rate of the river current, what is the rate of the current? 
Math
How do you set this up? Solve the system using substitution: A boat travels 18 miles downstream in 1.5 hrs. It then takes the boat 3 hrs. to travel upstream the same distance. Find the speed of the boat in still water and the speed 
Intermediate Algebra
in still water, a paddle boat averages 10 miles per hour. It takes the boat the same amount of time to travel 36 mile downstream, with the current as 24 miles upstream, against the current. What is the rate of the water's current? 
Math
A speed boat travels at a rate of 20 km per hour in still water. It travels 55 km upstream the same time it travels 90 km downstream. What is the rate of current? 
Math
in still water, a speed boat travels 5 times faster than the current of the river. If the speed boat can travel 48 miles upstream and then back in 5 hours, find the rate of the current. 
Science
A boat moves at a speed of 15 km/h in still water. The river it is traveling in flows at a rate of 3 km/h downstream. What is the velocity of the boat if it travels downstream? 
math
The speed of a river current is 4 mph. IF a boat travels 20 miles downstream in the same time that it takes to travel 10 miles upstream, find the speed of the boat in still water. 
math
a boat travels 10 miles upstream in 4 hours. the boat travels the same distance downstream in 2 hours. Determine the rate of boat in still water and the rate of the current?