U2 has a concert that starts in 17 minutes and they must all cross a bridge 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 one flashlight. 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 and other tricks like that are not needed to solve the problem. The solution is simply a matter of allocating resources in a certain order. 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 elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have passed and you have failed the mission.
This is one of my favorite brain teasers and I want to give you the satisfaction of figuring it out on your own. If you’re having a hard time, here’s a hint: There is a valid answer that doesn’t require tricks like throwing the flashlight or shining it backwards or having some other means of moving the flashlight.
There’s an assumption people often make that keeps them from solving this. Two members cross the bridge each time, but neither one of the two who crossed necessarily need to return. Think about how that would be possible. If you’re still stuck, use objects to simulate their movements. Use whatever you have laying around – pens, paper, erasers – and move them back and forth. Good luck!
An 18-wheeler is crossing a 4 kilometer bridge that can only support 10,000 kilograms and that’s exactly how much the rig weighs. Halfway across the bridge a 30 gram sparrow lands on the cab, but the bridge doesn’t collapse. Why not?
Since the bridge is 4 kilometers long, the halfway point would be 2 kilometers. The 18-wheeler would have used much more than 30g of fuel to drive 2 kilometers.
I’m easy to give yet few will take,
I’m shared with a bride and can be seen at a wake,
I have a monopoly on the young,
And at times, it’s true, I may have stung.
Advice. It’s easy to give it out but advice is often ignored. Brides are frequently given advice on their wedding day and you’ll even hear life advice at a funeral. Advice is frequently given to young people and some advice can be hard to stomach (like you should lose a few pounds).
Thanks to the comments, it doesn’t mean anything per se, but it’s a location in Zambia. If that’s all it is, it’s not really a brain teaser, but since we’ve already worked on it, I’m marking it as solved leaving it up for posterity.
Below are former attempts to solve it.
I have yet to figure this one out. NDOLA could mean And lo, or An old, among other things. Pamodzi on the other hand didn’t have any particularly meaningful anagrams. Both words together had over 1,000 anagrams.
I haven’t come up with any other possible meanings.