since time=distance/speed,
40/(20-x) = 60/(20+x)
A boat has a speed of 20 mph in still water. While traveling on a river at top speed, it went 40 miles upstream in the same amount of time it went 60 miles downstream. Find the rate of the river current.
4 answers
n still water, a boat averages 9 miles per hour. It takes the same amount of time to travel 26 miles downstream, with the current, as 10 miles upstream, against the current. What is the rate of the water's current?
n still water, a boat averages 9 miles per hour. It takes the same amount of time to travel 26 miles downstream, with the current, as 10 miles upstream, against the current. What is the rate of the water's current?
plug in the numbers 9 mi/hr, 26 mi, & 10 mi into the equation:
distance 1/(speed + x) = distance 2/(speed - x)
or
26/(9+x)=10/(9-x)
multiply both sides by (9-x)(9+x)
the denominators on either side can be cancelled, which then leaves the equation as
234-26x=90+10x
next, add/subtract like-terms
144=36x
x=4
distance 1/(speed + x) = distance 2/(speed - x)
or
26/(9+x)=10/(9-x)
multiply both sides by (9-x)(9+x)
the denominators on either side can be cancelled, which then leaves the equation as
234-26x=90+10x
next, add/subtract like-terms
144=36x
x=4