Need some help . Thank you !

Question

A particular algae can be grown at a rate of 30 grams per square metre per day, producing 0.048 litres of biodiesel with an energy density of 9.8 kWh per litre. If it was necessary to produce biodiesel with energy content of 4 kWh/p/d for every person in Australia (population 23 million), how many square kilometres of algae farm would be needed?

Answer 1

This is straight multiplication and division after you set it up.  Or, you can set it up stepwise instead of in a single equation.

 

1) You can ignore grams, because the problem has already given you teh number of litres produced.

 

2) Each person requires 4kWh per day. 

 

3) Each square meter produces 0.048 litres * 9.8 khW/litre per day = .4704 kWh/day/square meter per day

 

4) Divide 4 by .4704 giving 8.5034 square meters per person to produce their energy.

 

5) multiply 23 million * 8.5 = 195.6 million square meters,

 

6) Adjust scale - divide by 1 million square meters per square kilometer = 195.6 square kilometers.