To calculate the total cost of using each bulb, we can use the following formulae which include the cost of electricity:
Incandescent bulb: Total cost = R0.036 x Hours + R10.00
Fluorescent bulb: Total cost = R0.009 x Hours + R19.99
1. Identify which variable is the independent variable in the above equations. Give a reason for your answer.
2. Why is there ‘+ R10,00’ at the end of the Incandescent bulb equation?
3. Why is the rate used for the fluorescent bulb a quarter of the rate used for the incandescent bulb? (The rate is the value by which the hours is multiplied.)