Mr. Perks visits his friend by car. Luckily his friend lives also on the countryside so he has never to stop and he can drive constantly 30 kilometers per hour. It takes him 20 minutes to arrive at his friends house.
Mr. Perks buys a plant which is at the beginning 3 centimeters high. He observes that the plant is growing 5 millimetre per day the first half a year.
Mr. Perks wants to take a bath. His tub holds 100 liter of water. After 20 minutes his tub is completely filled.
Mr. Perks has finished his bath. Now he lets out the water of his bath tub, which clasps 100 liters of water. He measures: just 2 liters of water run off per minute.
