How many rubbish bins are needed? (2)

$$\text{Money left} = \text{Budget} - \text{Cost}$$ $$\text{Money left} = \text{R}110\,000 - \text{R}123\,900$$ $$\text{Money left} = -\text{R}13\,900$$

Since the result is negative, it means there is a deficit.

The amount of money left is $\boxed{-\text{R}13\,900}$ (or a deficit of R13 900).

$$\text{Number of trees planted} = \frac{3}{4} \times 48$$ $$\text{Number of trees planted} = 3 \times \frac{48}{4}$$ $$\text{Number of trees planted} = 3 \times 12$$ $$\text{Number of trees planted} = 36$$

There are $\boxed{36}$ trees planted around the playground.

$$\frac{3}{4} = 3 \div 4$$ $$\frac{3}{4} = 0.75$$

As a decimal, $\frac{3}{4}$ is $\boxed{0.75}$.

Let $x$ be the number of rubbish bins.

$$\frac{\text{Benches}}{\text{Rubbish bins}} = \frac{3}{2}$$ $$\frac{18}{x} = \frac{3}{2}$$

$$18 \times 2 = 3 \times x$$ $$36 = 3x$$

$$x = \frac{36}{3}$$ $$x = 12$$

You will need $\boxed{12}$ rubbish bins.