To find the equilibrium level of consumption (C), we need to plug in the given values into the consumption function.
The consumption function is given by:
\[ C = \text{R}100 \text{ billion} + 0.75 \times (Y) \]
where \(Y\) is the national income or output. In this case, \(Y\) is R300 billion.
Substituting \(Y\) into the consumption function:
\[ C = R100 \text{ billion} + 0.75 \times R300 \text{ billion} \]
Calculating the second term:
\[ 0.75 \times R300 \text{ billion} = R225 \text{ billion} \]
Now, adding both parts together:
\[ C = R100 \text{ billion} + R225 \text{ billion} = R325 \text{ billion} \]
Therefore, the equilibrium level is equal to R325 billion.