Unit Pricing involves finding out how much 1 of something will cost. It is commonly used for comparing prices of multiple items in shops, when the quantities and prices vary depending on the pack size.
Unit pricing involves dividing the price by the number of items in the pack: if 5 oranges are solve for £1.50, then 1 orange costs £1.50 ÷ 5 = £0.30. Using this method allows price comparisons to be made.
In some instances, where weight or volume is involved, use a unit of 100g or 100ml to simplify the calculations.
1. A supermarket has bread rolls on sale priced at 2 packs for £1.50. Each pack contains 6 rolls. It also has a jumbo packet of 20 rolls for £3.00. Which is better value for money?
Answer: The smaller packs
2 packs x 6 rolls = 12 rolls for £1.50.
The rolls are £1.50 ÷ 12 = 12.5p each.
The jumbo packet has 20 rolls for £3, which is £3.00 ÷ 20 = 15p each.
The smaller packs are better value.
2. 2 litres of laundry washing liquid costs £8.50, and will give 40 washes. A small box of laundry washing pouches gives 19 washes and costs £7.00. A large box of laundry washing pouches gives 30 washes and costs £8.00. Which is the best value?
Answer: 2 litres of liquid
Work out the cost her wash.
For the liquid: £8.50 ÷ 40 washes = 21.25p per wash
For the 19 pouch box: £7.00 ÷ 19 = 36.84p per wash
For the 30 pouch box: £8.00 ÷ 30 = 26.67p per wash
The liquid is the cheapest per wash.