Final answer:
In a proportional (flat) tax rate system, the marginal tax rate always equals the average tax rate because a flat percentage is applied uniformly to all income, making the answer true.
Step-by-step explanation:
In a proportional tax (flat tax) rate system, the marginal tax rate is equal to the average tax rate. This is because a proportional tax system taxes all income at the same fixed rate, regardless of the level of income. True is the correct answer to whether the marginal tax rate will always equal the average tax rate in such a system. For example, if the tax rate is 10% on all income earned, then both the tax on the last dollar earned (marginal) and the tax on the entire income (average) will be 10%.