Warren enters into a contract with Susan for the construction of a swimming pool in Susan's garden for $5,000. Of this, $2,000 is to be paid when the excavation is complete; $2,000 when the concreting has been done; and the balance "on final and satisfactory completion" of the work. The contract provides that the excavation is to be completed by April 1; that the concreting is to be done by May 1; and that the pool is to be finished and ready for use on June 1. It also provides that Susan is to be entitled to cancel if at any stage Warren is more than 2 weeks behind schedule with the work.

Soon after Warren has started to do the excavation, some of his workers fall ill, with the result that the work is delayed and the excavation is not completed until April 21. Susan is aware of these delays but does not exercise her right to cancel until May 16 when Warren (by dint of great efforts to speed up the work) has nearly finished the concreting.

On May 16, a reasonable person in Susan's position would have concluded that it was impossible for Warren to finish the work before June 7 at the earliest. Susan has paid Warren the $2,000 due on completion of the excavation, but has made no further payment.

Advise Warren as at May 17th.

Would it make any difference to your answer if, before the contract was signed, Susan explained she needed to have the pool ready for 1 June as her son has sent out invitations to his 21stbirthday party, a pool party to be held at Susan's home?