Using the IRAC Rule, please answer the question. John, an alcoholic, has an account with the local liquor shop (he pays the account every fortnight on payday). John recently purchased three bottles of very good quality Johnny Walker whisky while intoxicated. The barman, who realized that he was drunk and unable to understand what he was agreeing to, charged him double the regular price and he signed the account. Upon sobering up John realized what had happened and seeks your advice as to whether he must pay the full amount when he goes to settle the bill on payday. Must he pay a reasonable price? Advise John on his rights and responsibilities under the common law.