Determining If Class Grade Rules Are Functions

In a particular math class, the overall percent grade corresponds to a grade point average. Is grade point average a function of the percent grade? Is the percent grade a function of the grade point average? The table shows a possible rule for assigning grade points.

$$\begin{array}{ccccccccc}\text{Percent grade}& \text{0–56}& \text{57–61}& \text{62–66}& \text{67–71}& \text{72–77}& \text{78–86}& \text{87–91}& \text{92–100}\\ \text{Grade point average}& \text{0.0}& \text{1.0}& \text{1.5}& \text{2.0}& \text{2.5}& \text{3.0}& \text{3.5}& \text{4.0}\end{array}$$

OpenStax, Algebra and Trigonometry 2e · §3.1 Functions and Function Notation · Example 1