Unit pricing
The unit price of an object is the price for one unit. It is used to compare the value of objects.
Example
Which packet of biscuits is better value?
- 拢1 for 400 g
- 拢1.90 for 1 kg
It is hard to decide which item is better value if they are different sizes. So we must first work out the unit price for each packet.
400 g packet
Unit price = \(\frac{\text{price}}{\text{mass}}\)
Working in pence gives:
Unit price = \(\frac{100}{400}\)
The small packet cost 0.25 pence per gram.
1 kg packet
Unit price = \(\frac{\text{price}}{\text{mass}}\)
The units must be the same for the prices to be compared, so first convert kilograms to grams. 1 kg = 1,000 g.
Unit price = \(\frac{190}{1,000}\)
The large packet costs 0.19 pence per gram.
So the large packet is better value as the unit cost is lower.