To determine the denominator of the multiplier formula when given the marginal propensity to consume (MPC), we need to apply the provided formula for the multiplier, which is:
[tex]\[ M = \frac{1}{1 - \text{MPC}} \][/tex]
Given that MPC is 0.2, we follow these steps to evaluate the denominator:
1. The multiplier's denominator is given by [tex]\( 1 - \text{MPC} \)[/tex].
2. Substitute the given MPC value into the formula:
[tex]\[ 1 - 0.2 \][/tex]
3. Perform the subtraction:
[tex]\[ 1 - 0.2 = 0.8 \][/tex]
Thus, the denominator of the multiplier formula when the marginal propensity to consume (MPC) is 0.2 is equal to 0.8.