Best Buy Questions
Best buy questions ask you to work out which of two or more products gives the best value for money, by finding a common unit price such as the cost per 100 g, per litre or per item. They appear throughout GCSE Foundation and Higher calculator papers under ratio and proportion, often combined with percentages or offers.
Before you start
Make sure you're comfortable with these topics first:
Method
- Identify the quantity (weight, volume, or number of items) and the price for each product being compared.
- Divide the price by the quantity to find a unit price, such as price per 100 g, per litre or per item.
- Make sure both products are measured in the same units before comparing (convert kg to g, or litres to ml, first).
- Compare the unit prices directly: the smaller price per unit is the better value for money.
- Write a clear concluding sentence stating both unit prices and which product is better value.
Worked example
A shop sells jars of coffee. Jar A contains 200 g and costs 3.20 pounds. Jar B contains 350 g and costs 5.25 pounds. Which jar is better value for money?
- Jar A: price per 100 g = 3.20 / 200 x 100 = 1.60 pounds.
- Jar B: price per 100 g = 5.25 / 350 x 100 = 1.50 pounds.
- Compare the two unit prices: 1.50 pounds is less than 1.60 pounds.
- Final answer: Jar B is better value for money (1.50 pounds per 100 g compared with 1.60 pounds per 100 g for Jar A).
Practice questions
Try each question, then tap to reveal the answer.
Exam-style questions
Written in the style of a GCSE Maths exam paper, with a full mark scheme.
A supermarket sells tins of soup. Tin A contains 400 g and costs 76p. Tin B contains 600 g and costs 1.08 pounds. Which tin is better value for money? You must show your working.
A garden centre sells the same compost in two bag sizes. Small bag: 30 litres for 6.00 pounds. Large bag: 70 litres for 12.60 pounds. (a) Work out the price per litre of each bag. (2) (b) State, with a reason, which bag size is the best value for money. (2)
Two shops sell the same box of chocolates, normally priced at 18 pounds. Shop A takes 25% off the normal price. Shop B takes 5 pounds off the normal price, then takes a further 10% off that reduced price. Determine which shop offers the cheaper price, and by how much.
See real past-paper questions on best buy questions, organised by topic with official mark schemes →
Free printable worksheet
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