Riddle me this, riddle me that...

[a-mole]

Haha.. i found this on a webpage (http://www.thakur.demon.nl/index_1.html) and i thought, U2 makes even math cool... even though I am notreall ybothering witch solving

"U2 puzzle

U2 has a concert that starts in 17 minutes and they must all cross abridge to get there. All four men begin on the same side of the bridge.You must help them across to the other side. It is night. There is oneflashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each band member walks at a different speed. A pair must walk together at the rate of the slower man's pace:
Bono:- 1 minute to cross
Edge:- 2 minutes to cross
Adam:- 5 minutes to cross
Larry:- 10 minutes to cross
For example: if Bono and Larry walk across first, 10 minutes have elapsedwhen they get to the other side of the bridge. If Larry then returns withthe flashlight, a total of 20 minutes have passed and you have failed themission.

Can you get them across in 17 minutes?"

edit:// Larry takes 10minutes

 

[LindaS]

Well I guess Bono has to run back with the flashlight everytime (poor Bono ). But still, I don't see how they can get across in 17 minutes The only way i see it, Larry would have to go a little bit faster, maybe if there was a cat he could run away from or something
Ah well, i've never been good at math, so there will probably be a solution.

 

[geegeelovesadam]

I think I got it!

Send Adam across with Larry: 10 minutes total
Send Adam back with the flashlight, takes 5 minutes: 15 minutes total
Send Bono across with Edge, takes 2 minutes: 17 minutes total

Seeing as all the band members have now crossed the bridge, there would be no need to return the flashlight.

 

[Dismantled]

I hate math

 

[geegeelovesadam]

Oh wait... although it appears my original solution does work at first, I gotta figure out how to get Adam back across to the bridge...

here's the actual solution:


Bono and Edge go over, Bono comes back (3 minutes)
Larry and Adam go over, Edge comes back, (12 minutes)
Bono and Edge go over (2 minutes)

3 + 12 + 2 = 17

 

[Swingn2thaMusic]

I am so impressed that you got that! i've been sitting here for five minutes...and nothing! so congrats!

 

[edge's girl]

I hate math

i'm with you there. funny problem though. and well done geegeelovesadam I never would have got it.

 

[geegeelovesadam]

I am so impressed that you got that! i've been sitting here for five minutes...and nothing! so congrats!

Thanks! I can be quite the math geek at times

 

[faithingrace]

I once heard that this question came from a Microsoft employment application form. Could be urban legend.

 

[madonna's child]

I had to do this problem in my trigonometry class junior year of high school. I was super excited to see U2 invading such a boring subject.

 

[a-mole]

yeah.. i never had that problem unfortunately