Competition Three

Can you work out how much water these two kids are using in a week? It's your chance to win a real MiW labcoat signed by the guys.

Max hates it when his sister Rosie is right. She reckons that because she takes showers instead of baths, like him, that she cares more about the environment. 'Showers use less water,' she says. But Max argues that he keeps his baths shallow and only takes a bath three times a week, whereas she showers daily with a power shower and so uses more water.

To prove his sister wrong, Max has kept a log of how long her showers last and how much water he uses in the bath, which is typically about 80 litres. If the shower pumps water at 25 litres per minute but Rosie is only in the shower for 3 minutes, who uses the most water in the course of a single week?

This competition is now closed.