In a ship race Hana completed 20 km downstream in 3 hr. If the return trip took 4 hr 20 min, how fast can
she paddle in still water?

Question

In a ship race Hana completed 20 km downstream in 3 hr. If the return trip took 4 hr 20 min, how fast can
she paddle in still water?

hero · Answer

d = rt

20 = 3(r+w)
20 = (13(r+w))/3

aroub · Answer

Yes, this is what I did and then got a negative answer!

hero · Answer

well, the second equation is supposed to be r - w for upstream

hero · Answer

Let me finish solving

aroub · Answer

Okay

aroub · Answer

nvm, I think I did something wrong in the calculations -.-

anonymous · Answer

Calculated in jiffy, by any chance is it $ \frac{220}{39} km/hr$?

hero · Answer

FFM, I would swear that your comment is a violation of the code of conduct.

hero · Answer

Posting answers, with no steps and butting in while someone else is trying to help.

aroub · Answer

I got 95/3

anonymous · Answer

No need to get all bummed up. I was just testing my mind.

anonymous · Answer

Here is how I got that :

$$ x+y= 20/3 $$
$$ x-y= 20\left/\frac{13}{3}\right. $$

No solving for $ x$

anonymous · Answer

now*

hero · Answer

Yeah, I meant to do it that way

aroub · Answer

But you'll get x AND y, what do you do?

anonymous · Answer

x = speed in still water
y= speed of the steam/river

hero · Answer

That's why I used r and w

hero · Answer

Did anybody get r = 5.64103 and w = 1.02563

aroub · Answer

FFM did!

aroub · Answer

Okay.. Thanks a lot!!