unit conversion

Here is the scenerio:

Next month we're planning a trip from Montreal to Niagra Falls. My husband is going to run the Niagra Falls marathon, so we're going for the weekend.

Our car uses about 1 gas tank (50L of gas) for approximately 600km. The distance from Montreal to Niagra falls is 667km (you could get the students to look this up as an extra challenge). Also I plan to drive around in Niagra falls a bit (at least 84km, as I have to drive my husband to the start of the Marathon, which is 42km long, and then come back to the finish line in Niagra Falls).

When you own an outdoor swimming pool, in the spring you need to "shock" it, which means add a large amount of chlorine, in order to kill all the backteria and algea that accumulated over the fall/winter/spring. But chlorine is expensive, so you don't want to add too much (and waste it). In order to figure out how much to add, you need to figure out the volume of your pool, since the label on the chlorine tells you how much to add per litre of water.