How can you get a group of people across a bridge in a certain amount of time?

The set up is this: there are four people who need to get to the other side of the bridge, each with their own time needed to get across said bridge. Even worse, the bridge can only support two of them for each trip (and the person with the longer time is counted when traveling in the pair). Oh and it’s like dark and there is only one flashlight so a person who has crossed the bridge has to come back for a return trip in order to lead another person across once again. See, riddles are ‘fun’.

Person A can get across in 1 minute, Person B does it in 2 minutes, Person C crosses in 5 and slowpoke sloth human needs 10 minutes. You need to get everybody to the other side in under 17 minutes.

The Logician's Children

Two former college roommates, both logicians, meet at a conference after many years without contact. While catching up, the two eventually get around to discussing their children. The first logician asks the second how many children he has, and what their ages are. The second replies that he has 3 children, but (ever the logician) he will only reveal clues about their ages. The first logician must deduce for himself the ages of the second's children.

"First," says the logician, "the product of my children's ages is 36."

"Second, the sum of their ages is the same as our apartment number in college."

"Third, my oldest child has red hair."

Upon hearing the third clue, the first logician replies at once with the ages of his friend's children. What are they? How do you know?