Explanation:
Biscuits can be bought in packets of 12 or packets of 18. All biscuits are identical in size and quality. Packet of 12 biscuits for £0.78 Packet of 18 biscuits for £1.25 Which has better value?
pack of 12: £0.78 /12 = £0.065 each
pack of 18: £1.25 / 18 = £0.0694 each
The pack of 12 at £0.065 each is the better value.