(no subject)

[sereneorange]

Scooby snack for the first person who gives me the answer:

A fly is flying between two boys on bicycles who are peddling toward each other at 10 miles per hour. The fly reaches one boy, reverses immediately, and flies back to the other boy instantly, repeating the process each time. The fly is flying at 60 miles. The boys meet in thirty minutes. How far has the fly flown in that time?

Comments

[rainygirl.livejournal.com]

The boys start off 10 miles apart. That's as far as I got before I said screw this.

[serene-orange.livejournal.com]

lol. wussy

[rainygirl.livejournal.com]

I was over thinking this. The fly flies 30 miles. If he's going 60 mph for 30 minutes, then he's gone 30 miles. It doesn't matter how far apart the kids are or how fast they are going.

Trickery!

[serene-orange.livejournal.com]

see?!?! and you gave up so easy at first

[wakeupkent.livejournal.com]

gold star for emily!!


... is what your teacher would have said if their initial distance were at all relevant to the question :)

[serene-orange.livejournal.com]

lol

[rainygirl.livejournal.com]

gold star for ron!!


... is what your teacher would have said if you had read the whole thread. :)

http://megerber.livejournal.com/398339.html?thread=3134467#t3134467

[roshov.livejournal.com]

too far to not have been smacked!!

"The fly is flying at 60 miles" is that speed or distance? (MPH)??

[serene-orange.livejournal.com]

assuming it is at 60 mph.. otherwise, no need for the at in there.

[roshov.livejournal.com]

were you bored and made this up, or helping conner with his homework? :D

see icon:

[tydestra.livejournal.com]

Re: see icon:

[serene-orange.livejournal.com]

bad geek

Re: see icon:

[tydestra.livejournal.com]

Math people are just failures at everything else! :p You've seen a hot teacher in almost every subject, but when have you ever seen a remotely hot math teacher?

Re: see icon:

[serene-orange.livejournal.com]

I had a hot math teacher. College -Finite Math

Re: see icon:

[tydestra.livejournal.com]

1 in a 1000...

Flukes happen from time to time

[telly-says.livejournal.com]

Well if the boys meet in 30 minutes and the fly is going 60 mph, then the answer should be 30 miles, right?

[eonblue21.livejournal.com]

15 miles

the boys would have gone 5 miles if they met in 30 minutes. cut that in half for the fly going (assumingly) from the center of the two boys to one boy

2.5 miles

the fly is going 6 times faster, thus 15 miles

i could be entirely wrong, but it makes sense to me

[serene-orange.livejournal.com]

That is what everyone else has been getting, except Robert came up with some reason, that I now forget, why is it 30, but mathmatically impossible to come up with an exact answer. He went full on geeky with some fractions. Made sense yesterday. . .

[wakeupkent.livejournal.com]

oh you want math to support the answer! You've made the engineer in me very happy. I can do that.

First, let's convert the speeds into miles per minute.

Speed A = 1/6 mpm
Speed B = 1/6 mpm
Speed C = 1 mpm

The initial distance is 10 miles, so Object C (the fly) will meet Object B (the second boy) at 7t/6 = 10 (1/6 + 1 = 7/6), so after 8.571428571 minutes.
At that moment:
A and B have each traveled t/6, which equals 1.428571429 miles. The fly has traveled 1t, which equals 8.571428571 miles.
Calculate the distance left: 10 - 2(t/6) = 7.142857143 miles

Repeat the process. Now Object C will meet Object A (the first boy) at 7t/6 = 7.142857143. This time, t = 6.12244898. On this leg, the boys each traveled 1.020408163 miles (t/6), and the fly traveled 6.12244898 miles (1t). At the end of this leg, the distance left between the 2 boys is 7.142857143 - 2(1.020408163) = 5.102040816
miles.

I could keep going and going until the distance between the boys is infinitesimally small (though never actually 0), but let's look at the information so far:

1st meet at 8.571428571 minutes
2nd meet at 6.12244898 minutes
Add the two times together, and you'll see that 14.69387755 minutes have elapsed. The fly has, to this point, traveled 8.571428571 miles + 6.12244898 miles, for a total of 14.69387755 miles. Note how the time elapsed is equal to the distance traveled by the fly.

[eonblue21.livejournal.com]

so in my simple way of doing things, my conclusion of 15 wasnt so far off

neat :)

[wakeupkent.livejournal.com]

you were literally halfway there. :)

[wakeupkent.livejournal.com]

The reason you wouldn't get an exact answer is because at each meeting, less and less time is elapsing, at the same time that less and less distance is being covered. It really depends on how exact a calculation you want. Eventually, the fly will be traveling 1e-90 miles every 1e-90 minutes (I'm using this number as an arbitrary example), and that number will just keep getting smaller and smaller, though never actually reaching 0. It's like saying 2 boys start out standing 100 feet apart, and every 1 minute, they half the distance between themselves. At how many minutes will they meet?
A:100
B:50
C:25
D:12.5
E:6.25
F:3.125
G:1.5625
H:0.78125
I:0.390625
J:0.1953125
K:0.09765625
L:0.048828125
M:0.024414063
N:0.012207031
O:0.006103516
P:0.003051758
Q:0.001525879

at this point, the boys are standing about 1/100 of an inch away from each other, and you'd be hard pressed to be able to physically half the distance between them, but from a purely mathematical stand point, you can keep going and going to where time = infinity. The boys will never ever meet. Lovely, yes?

[serene-orange.livejournal.com]

that is so cool.

[wakeupkent.livejournal.com]

you mock me :(

[serene-orange.livejournal.com]

NO! seriously... I don't. I think it was cool.

man are you ever insecure about your nerdy abilities, you big girl.

[wakeupkent.livejournal.com]

so nerdy is cool now?

[serene-orange.livejournal.com]

is to me... but I do not exactly hold the litmus strips of cool, y'know, so you may still be a complete dork.

one more time, without the typos...

[wakeupkent.livejournal.com]

The boys meet in thirty minutes, meaning the fly has been traveling for 30 minutes at a speed of 60 miles per hour. Assuming that acceleration time is negligible, meaning that the fly goes from 0-60 instantly, the fly would have traveled 30 miles.

Re: one more time, without the typos...

[nevermind6794.livejournal.com]

Yeah, that sounds about right.

[onnotangu.livejournal.com]

grog hate maths
yah for bio chem.