1. In a laundry sink, the hot water tap lets out 3 litres of water every minute. The cold water tap lets out 4 litres of water every minute. If the sink is left unplugged, 2 litres of water are drained every
minute. With the sink unplugged, I turn on the cold water tap. Three minutes later, I turn on the
hot water tap as well. I leave both taps running for another 2 minutes before both taps are turned
off. How long do I now have to wait before the sink is completely emptied?

2. Fly the Super Spy is trying to unravel a secret three digit code. Fly knows that the first digit must
be an even number, and the last digit must be an odd number. How many different combinations
of the three digit code exist? (Note: zero is counted as an even number)