# Thread: Word Problem - Rates

1. ## Word Problem - Rates

Hi, I'm stuck on grade 11 review right now, and it's horrible because the material that I was taught completely changed after I went into grade 12 last year, so now I am stuck on this question, I believe it's too vague. But then again, I didn't keep any of my notes from previous years.

Rowing at 5 times the speed of the current, Jacob's team can travel 24km downstream in the same time it takes them to travel 16km upstream. What is Jacob's team's rate and the rate of the water?

2. Use the basic equation velocity=distance/time:

$\displaystyle v = \frac {d}{t}$

Which can be rearranged to get:

$\displaystyle t = \frac {d}{v}$

We know that the time to travel a distance of 16 upstream is the same as the time to travel 24 downstream, so:

$\displaystyle t_1 = t_2$

And:

$\displaystyle v_124 = v_216$

So we have that:

$\displaystyle v_1 = v_2(\frac {2}{3})$

Can you solve it now?

3. Hmm, I did begin with the velocity equation, however I don't understand why your last equation is like that. I mean I do, because I understand it takes the same amount of time to go upstream and downstream, but I wouldn't know what to do next, due to the fact isn't there the time variable missing, for they didn't give a time?

So wouldn't we have 2 unknowns?

We don't know the velocity nor the time, we just know within the certain time both directions & distance are completed simultaneously.