Calculate the amount that Tumi will be able to Invest in the bank, if he is going to invest the total amount he has set aside.

The amount Tumi will be able to invest is $\boxed{\text{R}19\,200}$.

1.2 Determine the Interest he will earn from the bank.

Principal ($P$) = R19 200 (from 1.1)
Interest rate ($i$) = 12.5% p.a. = 0.125
Time ($n$) = 36 months = $\frac{36}{12}$ years = 3 years

The interest Tumi will earn is $\boxed{\text{R}7\,200}$.

1.3 What is the total amount that he will receive at the end of the investment period?

The total amount Tumi will receive is $\boxed{\text{R}26\,400}$.

Question 2

2.1 Calculate how much Tumi had to put down as a deposit for the house.

The deposit for the house is $\boxed{\text{R}63\,135}$.

2.2 If Tumi uses the money he received from the bank at the end of his investment term, will he have enough to pay for the deposit? Show by means of calculations.

Amount received from bank = R26 400
Deposit required = R63 135

Since $\text{R}26\,400 < \text{R}63\,135$, Tumi will not have enough money to pay for the deposit using only the investment.
Tumi will need an additional amount of:

No, Tumi will $\boxed{\text{not have enough money}}$ for the deposit.

2.3 Tumi learns that he will have to pay a monthly instalment of R5 380 over a period of 20 years.

2.3.1 If the interest rate does not change, Show with calculations that the total amount paid, including the deposit will be R1 354 335.

The total amount paid, including the deposit, is indeed $\boxed{\text{R}1\,354\,335}$.

2.3.2 How much more money would Tumi have paid by the end of the 20 years?

Tumi would have paid $\boxed{\text{R}805\,335}$ more.

2.3.3 Calculate the percentage interest that Tumi would have paid by the end of 20 years if the monthly instalment did not change. Round your answer off to one decimal place.

The percentage interest Tumi would have paid is approximately $\boxed{165.7\%}$.