Quiz question, I need answers???

Question

There are four people in an adventure race that need to get across a lake. They have a small canoe. The rules say that only the slowest person in the canoe can paddle, only one or two can be in the canoe at a time, and they must all cross in the canoe. From practice, they know that:

Ann can paddle across in 1 minute.

Bill can paddle across in 2 minutes.

Sue can paddle across in 5 minutes.

Mike can paddle across in 10 minutes.

How do they get everyone across the river in the fastest time without breaking the rules?

Answer 1

There are five crossings, counting both directions. Bill paddles across with Ann, and returns alone. Then Mike paddles across with Sue, and Ann paddles back. Bill then paddles back with Ann. The total time is 17 minutes, which is the shortest possible, although Ann could have done the second crossing, and Bill from the fourth, and the result would be the same. The crucial point is that Sue and Mike had to make the third crossing.

Answer 2

email me the answers pls

Answer 3

10 and 1 go over, 1 comes back, 5 and 1 go over, 1 comes back, 2 and 1 go over.    -19mins