Solve problems in everyday life 8.1 Calculate the number of glasses of juice that can be served if each glass can hold 280 ml of juice. 8.2 How many glasses of juice can be served if each glass can hold 210 ml of juice?

$$\text{Total volume of juice} = 9750\, \text{L}$$

Since $1\, \text{L} = 1000\, \text{ml}$,

$$\text{Total volume of juice} = 9750 \times 1000\, \text{ml} = 9\,750\,000\, \text{ml}$$

$$\text{Number of cartons} = \frac{\text{Total volume of juice}}{\text{Volume per carton}}$$ $$\text{Number of cartons} = \frac{9\,750\,000\, \text{ml}}{500\, \text{ml}}$$ $$\text{Number of cartons} = 19\,500$$

The number of 500 ml juice cartons is $\boxed{\text{19 500}}$.

$$\text{Number of cartons} = \frac{\text{Total volume of juice}}{\text{Volume per carton}}$$ $$\text{Number of cartons} = \frac{9\,750\,000\, \text{ml}}{250\, \text{ml}}$$ $$\text{Number of cartons} = 39\,000$$

The number of 250 ml juice cartons is $\boxed{\text{39 000}}$.

$$\text{Volume per box} = 1.5\, \text{L}$$ $$\text{Total volume of juice} = 12 \times 1.5\, \text{L} = 18\, \text{L}$$

Since $1\, \text{L} = 1000\, \text{ml}$,

$$\text{Total volume of juice} = 18 \times 1000\, \text{ml} = 18\,000\, \text{ml}$$

$$\text{Number of glasses} = \frac{\text{Total volume of juice}}{\text{Volume per glass}}$$ $$\text{Number of glasses} = \frac{18\,000\, \text{ml}}{280\, \text{ml}}$$ $$\text{Number of glasses} \approx 64.2857$$

Since only whole glasses can be served, we take the floor of this number.

$$\text{Number of glasses} = 64$$

The number of glasses of juice that can be served is $\boxed{\text{64}}$.

$$\text{Number of glasses} = \frac{\text{Total volume of juice}}{\text{Volume per glass}}$$ $$\text{Number of glasses} = \frac{18\,000\, \text{ml}}{210\, \text{ml}}$$ $$\text{Number of glasses} \approx 85.7142$$

Since only whole glasses can be served, we take the floor of this number.

$$\text{Number of glasses} = 85$$

The number of glasses of juice that can be served is $\boxed{\text{85}}$.