Question

Once there four boys who wanted to cross a street. They were all on the same side. It was night time and they only had one flashlight between them. Only two boys can cross the street at a time, and anyone who crosses , either one or two people, must always have a flashlight with them. For his work, the flashlight must be walked back and forth. It cannot be thrown or forgotten. Another issue is that each boy walks at a different speed. A pair must walk together al the speed of the slower boy. Listed below is the amount of time each boy needs to cross the street:

Boy # 1needs 1 minute
Boy # 2 needs 2 minute
Boy #3 needs 5 minute
Boy # 4 needs 10 minutes

How can all four boys cross the street in 17 minutes ?