Eric asks his very close friend Michael, "Would you like to buy my excellent 1998 Commodore for $2000?" Michael accepts Eric's offer because he has always wanted that particular model of car. They agree to meet at the SCU car park on Friday at 1.00 pm when Eric will hand over the car and Michael will hand over the $2000 in cash.
They meet at the agreed time and place and Eric hands over the car, keys and signed registration papers to Michael. But, in his rush to get to an important meeting, Eric doesn't check the money in the envelope. Later that evening he discovers that Michael has paid him 2,000 in Hong Kong dollars which equals just 360 Australian dollars. When Eric tells Michael that he was supposed to pay 2,000 Australian dollars, Michael points out that there was no agreement about any particular national currency and all he was required to do under the contract was pay $2,000, which he had done.
Eric seeks your advice as to whether or not he can sue Michael for a breach of contract, claiming that Michael was required to pay him AUD 2000, not HKD 2000 even though there had been no mention of currency at the time of the agreement. What is your advice?