A school purchased a printer for R250 000. The printer depreciates at 10% p.a. on a reducing balance method. The printer will be replaced after 5 years. The inflation rate during this period is 8% per annum. Calculate the book value of the printer at the end of the 5 year period.

The formula for depreciation on a reducing balance is $A = P(1 - i)^n$, where $A$ is the book value, $P$ is the initial cost, $i$ is the depreciation rate, and $n$ is the number of years.

The book value of the printer at the end of 5 years is $\boxed{\text{R147 622.50}}$.

5.1.2 Calculate the cost of a similar printer when the 5 year period expires.

The formula for future value with inflation is $A = P(1 + i)^n$, where $A$ is the future cost, $P$ is the current cost, $i$ is the inflation rate, and $n$ is the number of years.

The cost of a similar printer after 5 years is $\boxed{\text{R367 332.02}}$.

5.1.3 Calculate the amount of money that must be saved in order to have enough money to replace the printer in 5 years.

The school sells the used printer for 95% of its book value (from 5.1.1).

The amount to be saved is the cost of the new printer (from 5.1.2) minus the selling price of the old printer.

The amount of money that must be saved is $\boxed{\text{R227 090.64}}$.

5.2.1 Determine which bank offers the best interest rate.

Bank A offers an effective interest rate of $12\%$ per annum.

Bank B offers a nominal interest rate of $11.5\%$ p.a., compounded monthly.
The formula for the effective annual rate is $i_{eff} = \left(1 + \frac{i_{nom}}{m}\right)^m - 1$.
Here, $i_{nom} = 0.115$ and $m = 12$.

Bank A effective rate: $12\%$
Bank B effective rate: $12.13\%$
Since $12.13\% > 12\%$, Bank B offers a better interest rate.
$\boxed{\text{Bank B}}$ offers the best interest rate.