After a long way, a truck driver ends up in front of a tunnel. He can not get through without severely damaging his truck, because the tunnel has a height of 3.00 meters, while his truck has a height of 3.01 meters. The driver would like to pass the tunnel because the other way will take him at least 1 hours. Suddenly he gets a great idea, he immediately starts doing some things and after 10 minutes he is back on track on the other side of the tunnel. What was the great idea of the truck driver?

Imagine you are a pilot of a plane. You are going to fly a plane from Northern Maine to Los Angelos, California, which is 3000 miles. It takes 10 hours. You drive to a hotel in LA which is 18 miles from the airport. The next day, you wake up and drive back to the airport which is another 18 miles. You fly another plane up to Vancouver, Canada which is 700 miles. When you arrive in Canada, you go into the employees lounge and you sleep at the airport that night. The next day, you fly a long trip to Sydney, Australia which is 10,000 miles. You stay in Sydney for 3 days, and then you fly all the way back to Northern Maine, where your home is. The flight is 12,000 miles. How may miles did you go in total and how old is the pilot?

Suppose you would like to boil an egg for exactly 15 minutes. But you only have two hourglasses, one of zeven and one of eleven minutes. What is the the fastest way to do this?