### a) Real Interest Rate
The real interest rate is calculated by adjusting the nominal interest rate for inflation. It is given by the formula:
\[ \text{Real Interest Rate} = \text{Nominal Interest Rate} - \text{Inflation Rate} \]
If inflation turns out to be higher than what the borrower and lender expected, this means that the actual inflation rate is higher than the expected rate used to set the nominal interest rate. Given that the


