The energy consumption in a region increases at a rate of 4% every year. Assuming that the rate remains constant, in how many years will the energy consumption quadruple? What are the environmental...

The energy consumption in a region increases at a rate of 4% every year. Assuming that the rate remains constant, in how many years will the energy consumption quadruple?

What are the environmental benefits and possible challenges of storing and purifying rainwater on site for domestic use?