A histogram is drawn for the daily water usage (in litres) of some households with the following class intervals:
0–50 l, 50–100 l, 100–200 l. The corresponding bar heights are 8 cm, 6 cm and 3 cm. The vertical axis shows frequency density using the scale 1 cm = 0.1 households per litre.
(i) Find the number of households in each class.
(ii) Hence, determine the total number of households represented in the histogram.