Joseph requested Amos to transport his goods from Gulu to Kamapla city for the sum of 500,0000. Amos replied that he was only prepared to transport the goods for 600,000/-. Joseph wrote back to Amos asking him to consider the initial price BUT Amos did not reply to his letter. Two days later, Joseph delivered the goods to the premises of Amos who transported the goods to Kampala. Joseph afterwards refuses to pay the sum of 600,000/-demand by Amos saying that there was no concluded contract.

b) Elucidate the circumstances under which a valid agreement may be set aside. (12 marks)