Question
A bicycle shop displays a road bike in its window with a sign reading 'Special offer — £450'. A customer enters the shop, says 'I accept your offer and will take the bike for £450', and holds out her bank card. The shop manager explains that the sign should have read £650 and refuses to sell at £450.
Suggested time: about 2 minutes. Choose the single best answer, then read why each option is right or wrong.