Help...More Math Help!!!...Please!

posted by .

A kayaker paddled 2 hours with a 6 mph current in a river. The return trip against the same current took 3 hours. Find the speed the kayaker would make in still water.


The speed is 6 mph slower going upstream and 6 mph faster going downstream. Distance traveled = time x speed. The distance for both is equal. Let X = the speed in still water.

With the above information, you should be able to develop the equation and solve it for X.

I hope this helps. Thanks for asking.

Let y = speed of the kayaker.
distance = rate x time.
For the trip down stream, his rate is y+6 and his rate back up stream is y-6.
The distance traveled is the same; therefore,
upstream rate x time = downstream rate x time
(y-6)*3hrs=(y+6)*2hrs
Solve for y.
Post your work if you get stuck.

You just give names to the variables you don't know and write down the equations.

The speed the kayaker in still water? Don't know? Let's call it v.

Then the speed when travelling with the current is
v + 6 mph.

The distance traveled in the two hours is:

(v + 6 mph)* 2 hours

let's call this d, so we put:

d = (v + 6 mph)* 2 hours

The speed on the return trip is
v - 6 mph

The time mneeded for that is given to be 3 hours, but it is also equal to the distance divided by the speed. So, you have that:

d/(v-6 mph) = 3 hours -->


(v + 6 mph)* 2 hours/(v-6 mph) = 3 hours --->

(x+6)/(x-6) = 3/2

where x = v/(mph)

x + 6 = 3/2 x - 9 --->

1/2 x = 15 --->

x = 30 -->

v/(mph) = 30 --->

v = 30 mph

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Word Problems!!

    PLz help me!These questions are on my study guide for tommorrow's test and I don't get them.Please help me solve them because I don't have a lot of time because I have to go to Chruch in 20 minutes.PLease help!Thanks! 1.Six pears and …
  2. math

    donna took 3hours to row 18 km upstream. her return trip took 1 hour less. find the rate of rowing in still water and the rate of the current. let the speed of her rowing in still water be x km/h, let the speed of the current be y …
  3. Math

    A kayaker paddled 2 hours with a 6 mph current in a river. The return trip against the same current took 3 hours. Find the speed the kayaker would make in still water.
  4. Algebra

    on a canoe trip, Rita paddled upstream (against the current) at an average speed of 2 mi/hr relative to the riverbank. on the return trip downstream (with the current), her average speed was 3 mi/hr. find rita's paddling speed in still …
  5. Algebra

    Cody’s motorboat took 3 hr to make a trip downstream with a 6-mph current. The return trip against the same current took 5 hr. Find the speed of the boat in still water
  6. Math

    A tour boat on a river traveled 40 miles downstream in 4 hours. The return trip against the current took 5 hours. What was the rate of the current?
  7. Math

    1.A tour boat on a river traveled 40 miles downstream in 4 hours. The return trip against the current took 5 hours. What was the rate of the current?
  8. algebra

    Chen's motorgoat took 3 hr to make a treip downstream with a 6-mph current. The return trip against the same current took 5 hr. Find the speed of the boat in still water.
  9. math

    The Connecticut River flows at a rate of 5 km / hour for the length of a popular scenic route. If a cruiser to travels 4 hours with the current to reach a drop-off point, but the return trip against the same current took 6 hours. Find …
  10. Algebra

    The Connecticut River flows at a rate of 3 km / hour for the length of a popular scenic route. If a cruiser to travels 3 hours with the current to reach a drop-off point, but the return trip against the same current took 7 hours. Find …

More Similar Questions