Question

Abi has 20 cents. She bought x pencils for 3 cents each. If y is equal to the number of cents left. write an equation that shows the dependence of y on x. What is the domain of the function

Answer 1

The equation that shows the dependence of y on x is y = 20 - 3x. The domain of the function is x ≥ 0 and x ≤ 20/3.

Step-by-step explanation:

To write an equation that shows the dependence of y on x, we need to first determine the total cost of the pencils Abi bought. Since each pencil costs 3 cents and Abi bought x pencils, the total cost of the pencils is 3x cents. Abi started with 20 cents and spent 3x cents on pencils, so the number of cents left, y, can be calculated as:

y = 20 - 3x

The domain of this function represents the possible values for x. Since x represents the number of pencils bought, it cannot be negative or greater than the number of pencils Abi can afford given her initial amount of 20 cents. Therefore, the domain of the function is x ≥ 0 and x ≤ 20/3.