The given situation is about the value of quarters and the number of quarters. If we think this through, we would deduct that the value of quarters depends on the number of quarters there are, for example, if there are 4 quarters, then the value is 1 dollar, and so on.
Hence,
The independent variable is the number of quarters.
The dependent variable is the value of the quarters.
The equation would be v = 0.25n.
If the input is 10, it means n = 10.
The output would be 2.5.