Mbathera trades in his old car on a new car at Special Wheels Motors. The parties agree that the price for the new vehicle is N$ 150 000 and they place a trade-in value of N$ 50 000 on the old car. Mbathera pays N$ 100 000 and drives away in his new car. Special Wheels Motors finds out later that the gear box of the old vehicle has to be repaired for N$ 10 000 and that Mbathera concealed the noise the broken gear box makes by putting some bananas in the gear box. The value of the old car is in fact not N$ 50 000, but N$ 40 000. Special Wheels Motors wants to know: 1) whether they concluded a valid contract of sale or an exchange and 2) whether it would be able to claim N$ 10 000 from Mbathera as a price reduction. Discuss fully.