17 minutes

There are 4 men who want to cross a bridge. All of them begin on the same side.

You have 17 minutes to get all of them across to the other side.

It is night time. There is only 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/delivered back and forth, it cannot be thrown, etc. Each man walks at a different speed. A pair must walk together at the rate of the slower man's pace.

Man 1 takes 1 minute to cross.

Man 2 takes 2 minutes to cross.

Man 3 takes 5 minutes to cross.

Man 4 takes 10 minutes to cross.

For example if Man 1 and Man 4 walk across first. 10 Minutes have elapsed when they get to the other side of the bridge. If Man 4 returns with the flashlight. A total of 20 minutes have passed and you have failed the mission.

See how quick you can solve this! (An average person can solve it within 2 minutes, whereas an under-average person gives up before a minute is up.) read answer below only if you need to

Man 1 and 2 cross the river 1st (2 mintues)
Man 1 comes back with flaslight (1 minute)
Man 3 and 4 cross the river with flashlight (10 minutes)
Man 2 comes back with flashlight (2 minutes)
Finally, man 1 and 2 cross the river with flashlight(2 minutes)
Total time is 17 minutes, weeeeeeeeeeee, not so hard huh?