Variation, Inequalities and Graphing
If a customer has a lawn that is watered regularly, the amount of a customer’s water bill can be modeled using the following combined variation equation.
In the equation, W is the amount of the water bill, T is the average daily temperature for the month, A is the area of the lawn, N is the number of people living in the home, and R is the average monthly rainfall in inches. Using what we know about variation, we see that W varies directly as T, A, and and inversely as R, and 0.0026 is k, the constant of variation.
Calculate your water bill under the following conditions.
- To determine T, choose a month and do an internet search for the average daily temperature in your area.
- Choose a lawn area, A, between 200 ft2 and 5000 ft2.
- For N, use the number of people living in your home.
- Using the same month you used to find T, find R by doing an internet search for the average monthly rainfall (in inches) in your area.
Show the original equation and all steps used to solve it. Since this is a money amount, remember to give your answer in dollars and cents. Review an example of a response for this Discussion.