Help river crossing confusion =(

In summary, A woman can row a boat at 6.3 km/h in still water and is crossing a river with a current of 3.2 km/h. To reach a point directly opposite her starting point, her boat must be headed at a 90 degree angle (perpendicular to the shore). It would take approximately 52 minutes for her to cross the river.
  • #1
j_confused
6
0
Woo. Nevermind the rest of this message. I figured it out =))))



Hello all :)

Am having brain fart, I need help (obiviously) from the experts! All the tutorials and examples about the classic boat crossing a river aren't helping me with this problem.

"A woman can row a boat at 6.3 km/h in still water. (Assume i points to the far side of the river, perpendicular to the current, and j points in the direction of the current.)"

At this point, I drew a diagram. As for vectors, i is 105 m/min [answers require meters/minutes] perpendicular to shore, I assumed current to be heading east (downriver in my drawing).
___________________________________
...^...105 m/min i......|
...| .........5500m
...|.........|
...--------> 0 m/min j......|

This makes sense, b/c it would take roughly 52 mins to cross to a point directly across. Then comes the confusing bits...

(a) If she is crossing a river where the current is 3.2 km/h, in what direction must her boat be headed if she wants to reach a point directly opposite her starting point? (in degrees)

(b) How long will it take her to cross the river? (in minutes)


Based on the above, i is still 105 m/min and j is now ~53.3 m/min, so the resultant would be 117.5 m/min... I think.
From there, I'm lost. Please help!

-Jen
 
Last edited:
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  • #2
90 degrees- tan-1(6.3/3.2)

is the angle
 
  • #3
what your email and ill send you a good diagram
 

FAQ: Help river crossing confusion =(

1. How does the river crossing confusion problem relate to science?

The river crossing confusion problem is a classic problem in the field of mathematical logic and computer science. It involves finding the most efficient way to transport a group of people or objects across a river while adhering to certain constraints, such as the number of people that can fit in a boat or the presence of dangerous animals. Researchers use this problem to study computational complexity and develop algorithms.

2. What is the origin of the river crossing confusion problem?

The origins of the river crossing confusion problem can be traced back to ancient China, where it was used as a brain teaser for military officers to test their strategic thinking and problem-solving skills. It gained popularity in the western world in the 19th century thanks to the work of mathematicians and philosophers, such as Charles Lutwidge Dodgson (aka Lewis Carroll) and George Boole.

3. How is the river crossing confusion problem relevant in modern times?

The river crossing confusion problem has many real-world applications, such as in logistics and transportation. It also serves as a model for understanding complex decision-making processes and has been used in artificial intelligence research. Additionally, the problem remains a popular puzzle for recreational and educational purposes.

4. What are some common strategies for solving the river crossing confusion problem?

There are several approaches to solving the river crossing confusion problem, including trial and error, heuristic algorithms, and mathematical proofs. Some common strategies include identifying and eliminating impossible solutions, finding patterns and shortcuts in the problem, and breaking it down into smaller, more manageable sub-problems.

5. Are there any variations of the river crossing confusion problem?

Yes, there are many variations of the river crossing confusion problem, each with its own set of rules and constraints. Some examples include the wolf, goat, and cabbage problem, the missionaries and cannibals problem, and the jealous husbands problem. These variations allow researchers to explore different aspects of the problem and develop new solutions and techniques.

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