All Puzzles

A man is going to an Antique Car auction. All purchases must be paid for in cash. He goes to the bank and draws out $25,000.

Since the man does not want to be seen carrying that much money, he places it in 15 envelopes numbered 1 through 15, in such a way that he can pay any amount up to $25,000 without having to open any envelope. Each envelope contains the least number of bills possible of any available US currency (for example, no two tens instead of a twenty).

At the auction, he makes a successful bid of $8322 for a car. He hands the auctioneer envelopes 2, 8, and 14. After opening the envelopes, the auctioneer finds exactly the right amount.

The question: How many ones did the auctioneer find in the envelopes?

Four men want to cross a bridge. They all begin on the same side. It is night and they have only one flashlight with them. At most two men can cross the bridge at a time and any party who crosses, either one or two people, must have the flashlight with them. The flashlight must be walked back and forth: it cannot be thrown, etc. Each man walks at a different speed. A pair must walk together at the speed of the slower man. Man 1 needs 1 minute to cross the bridge, man 2 needs 2 minutes, man 3 needs 5 minutes, and man 4 needs 10 minutes. For example, if man 1 and man 3 walk across together, they need 5 minutes.

How can all four men cross the bridge in 17 minutes?