I am trying to find all the solutions and put them together at a single place, So feel free to add comments and if you have a solution please do post. Cheers … 🙂
Here is the puzzles link : http://www.wuriddles.com/
Four people, A, B, C, and D, are on one side of a bridge, and they all want to cross the bridge. However, it’s late at night, so you can’t cross without a flashlight. They only have one flashlight. Also, the bridge is only strong enough to support the weight of two people at once. The four people all walk at different speeds: A takes 1 minute to cross the bridge, B takes 2 minutes, C takes 5 minutes, and D takes 10 minutes. When two people cross together, sharing the flashlight, they walk at the slower person’s rate. How quickly can the four cross the bridge?
Note: Supposedly a classic Microsoft question.