Final answer:
The independent variable is the number of rides completed by the taxicab driver, and the dependent variable could be the total earnings.
Step-by-step explanation:
The independent variable in this scenario is the number of rides completed by the taxicab driver, which is 20 rides per day. The dependent variable is not mentioned in the question, but it could be something like the total earnings of the taxicab driver, which would depend on the number of rides completed.
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