# Math problem

**URL:** <https://forum.kirupa.com/t/math-problem/183916>\
**Category:** flash\
**Created:** [March 31, 2006, 5:08am UTC](https://forum.kirupa.com/t/math-problem/183916 "2006-03-31T05:08:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![NANO3](https://avatars.discourse-cdn.com/v4/letter/n/c2a13f/32.png) [@NANO3](https://forum.kirupa.com/u/NANO3)\
**Post date:** [March 31, 2006, 5:08am UTC](https://forum.kirupa.com/t/math-problem/183916/1 "2006-03-31T05:08:12Z")

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it’s a tricky one

a boat travels downstream 300 miles in the same time that it travels upstream 200 miles…if current is constant, wut is the speed of the boat in still water

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**Author:** ![hl1](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/hl1/32/849_2.png) [@hl1](https://forum.kirupa.com/u/hl1)\
**Post date:** [March 31, 2006, 5:32am UTC](https://forum.kirupa.com/t/math-problem/183916/2 "2006-03-31T05:32:52Z")

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250 miles / time?

(/ being divided by)

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**Author:** ![kirupa](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/kirupa/32/11616_2.png) [@kirupa](https://forum.kirupa.com/u/kirupa)\
**Post date:** [March 31, 2006, 6:18am UTC](https://forum.kirupa.com/t/math-problem/183916/3 "2006-03-31T06:18:17Z")

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I am getting what harish posted. Is there one correct solution for this? There can be a near infinite set of solutions, because there are two unknowns (the boat’s speed, and the current’s speed). Manipulating both of those unknowns can give you any host of solutions for traveling 300m downstream and 200m upstream in the same time.

**Case 1: Downstream**  
300m = (boat\_speed + current\_speed)\*t

**Case 2: Upstream**  
200m = (boat\_speed - current\_speed)\*t

Combining both equations, the current’s speed is removed, and you are left with **250m = t\*boat\_speed**.

:hr:

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<div class="post-metadata">

**Author:** ![hl1](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/hl1/32/849_2.png) [@hl1](https://forum.kirupa.com/u/hl1)\
**Post date:** [March 31, 2006, 6:38am UTC](https://forum.kirupa.com/t/math-problem/183916/4 "2006-03-31T06:38:48Z")

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Yep. As I explained to him on IM.

I don’t understand what he finds challenging about it 😃

x+y=300  
x-y=200  
x=200+y  
200+2y=300  
2y=100  
y=50 (current)  
200+50=250  
300-50=250

or you could get the mean of the two numbers.