Dorcas of Naud Motors agrees to sell a second-hand motor car to Thoriso for R100 000. The parties agree that Dorcas will put new tyres on the car and do certain other minor repairs and that Thoriso will bring a cheque for the price when he calls to collect the car at the end of the week. Later that day, when Dorcas takes the car across town to have new tyres put on it, she negligently collides with a bus, and the car is damaged beyond repair. Dorcas argues that she is excused from liability in terms of the contract because the subject matter has effectively been destroyed. Advise(15)