Cross the Bridge

There are four people who can cross a bridge in 9 , 2, 5 and 1 min respectively. They need a torch to cross the bridge, the battery in the torch will last only for 17 min. How will all the four people cross the bridge.
Conditions:
1. Only two people can cross the bridge at one time.
2. They need to take torch along with them while crossing the bridge.

is it really possible
i think it vil take 18 mins to cross d bridge

let A be the src and B be the destination..

A -> B = ( 9 , 1) = 9 minutes..

B -> A = let 1 travel for 30 secs so that it reaches the middle of the bridge.Now he will ask 2 which is on the side A to cross the bridge by assisting him using the torch (direction A->B). now 1 will travel for another 30 secs to reach side A. Total minutes = .5 + 2 + .5 = 3

A -> B = (5,1) = 5 minutes..

Total time = 9 + 3 + 5 = 17 minutes..

dats ridiculous

i can even say dat the torch was needed.
It wasnt specified dat only wen it is glowing one can cross d bridge

unleashed wrote:dats ridiculous

i can even say dat the torch was needed.
It wasnt specified dat only wen it is glowing one can cross d bridge

Well, there is something called as common sense. I won't keep a torch just for fun. I would rather use it as a light source.

Well Buddy, the conditions are:
1)Two people have to walk together at a time to cross the bridge.
2)Out of the two people who are walking, one has to carry a torch which is glowing.

Ok Buddy, this is definitely possible. If you try with multiple combinations, you will definitely arrive at solution. All the best

Suppose there are four person A,B,C,D such that A takes 1 min,B takes 2 min, C takes 5 min, D takes 9 min to cross the bridge.

So first A&B will go. so 2 min over.
Now B will come back with torch. 2 more min over.i.e totally 4 min over.
Now C&D will go. so 9 min over. i.e totally 13 min over.
Now A will come back torch.so 1 min over.i.e totally 14 min over.
Now A&B will go so 2 more min over.i.e totally 16 min over.

So, all of them had crossed the bridge in 16 min only. we have 1 min more in torch...

Cool Sneha....Its a correct reply...Congrats

this was taught in softskills training prog @ NIE

oh...that is great, then we should expect many more replies in this thread.

its better not to reveal the answer after someone posts it bec the others wont even try for it as u ppl r revealing if its correct ot not

We will take care of it buddy from next time.Only after we have had ample amount of discussion on the topic, we will reveal the correct answer.

thanks alot really it helps us because i have joined now and i want to ans some Q but already they have been answered by gr8 minds !!!I m posting my views for g.d pls check them and i will be happy if corrections are made!!!