Suppose the marginal propensity to consume (mpc) is either 0.4, 0.85, or 0.65. a. for each value of the mpc, calculate the impact of a one-dollar decrease in taxes and the impact on gdp. instructions: enter a number rounded to one decimal place in each blank. mpc 0.4 0.85 0.65 b. for each value of the mpc, calculate the impact on gdp of a $250 million decrease in taxes . instructions: enter a number rounded to one decimal place in each blank.