Author 
Topic 

Copelank
New Member
USA
2 Posts 
Posted  08/26/2007 : 16:07:11

Here is my problem: Two cars 30 miles apart start toward each other, each traveling at 30 mph. At the same time the cars are set in motion, a bee flies off one of the cars, flying at 60 mph, meets the oncoming car, and then continues to fly back and forth from one car to the other until the cars meet. How many miles did the bee fly?
I know the formula D=R(T) is part of it, but don't know where to go from there. Math is not my strong point and word problems make me cringe. Pleas help!!!!!! Thank you for your time. 


sahsjing
Advanced Member
USA
2399 Posts 
Posted  08/26/2007 : 16:12:49

Find the time first, and then you can easily find the distance.



deff
Junior Member
USA
5 Posts 
Posted  08/27/2007 : 03:22:32

Is this a probability and stat problem???
Well, I would go about it by first think of the time (as sahsjing said) that the fly flew. This would be equal to the time that the cars travel, would it not?
So, if you can find out how long the cars took to meet each other, you have the Time for D=RT formula. The rate is given to you, as the rather fast bee travels at 60Mph the whole time.
Then you have R and T! 


Subhotosh Khan
Advanced Member
USA
9116 Posts 
Posted  08/27/2007 : 06:43:42

This is a very famous puzzle problem  in which Physicist and Mathematicians (apparently) solve it by different approach.
To a physicst:
Since the cars are drivng with constant equal speed  they will meet at the middle  30 minutes later.
In the mean time, the bee would fly 30 miles (60 mph  constant speed).
It takes about 7 seconds to solve the problem.
It seems mathematicians are capable of making quite a mess of this problem  by introducing summation of infinite series and take (on an average) 1/2 hour to solve the problem. Except for von Neumann  who took 7 seconds to solve the problem by adding infinite series!!! 
Edited by  Subhotosh Khan on 08/27/2007 07:10:51 


HallsofIvy
Advanced Member
USA
78 Posts 
Posted  08/28/2007 : 09:05:11

That's a very old joke and probably not true. (But still good)
Obviously you COULD do the problem by calculating the time the bee takes to fly from the first car to the second, then the time to fly back to the first car, ... getting an infinite sequence and summing that. A remarkably hard problem!
The story is that a person posed the problem to VonNeuman who thought for a few seconds and then gave the correct answer. The person chuckled and said "You know some people try to do that by summing the infinite sequence". VonNeuman looked puzzled and said, "But that's what I did!"
It is, of course, a slander on mathematicians. Any decent mathematician would immediately see that the bee is constantly in flight so, since the direction of flight doesn't matter, multiply his speed by the length of time until the cars meet. 


sahsjing
Advanced Member
USA
2399 Posts 
Posted  08/28/2007 : 18:46:27

Very nice story!




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