Case 03:S sold to B a house. After the sale, B discovered that the main posts of the house and other interior parts had been destroyed by termites and as a result, the house is in danger of collapsing. The defects of the house were hidden and concealed and were unknown to B until closer inspection was made by him. Is S liable for the defects? What are the remedies that B can elect on the contract?

Case 04:S Sold to B a tractor payable at P5,000 upon delivery and the balance of P7,000 within 60 days. B failed to take delivery of the tractor and pay the purchase price. S was forced to sell the same to a third person for only P10,000. Is B liable for the difference of P2,000?Why or why not?

Case 05: S executed a document whereby he agreed to transfer to B "the whole of the right, title and interest" in a business. This was 4/173 of the entire net value of the business. The parties agreed that the price should be 4/173 of the total net value. The ascertainment of such net value was left unreservedly to the judgment of the appraisers. Is the price certain? Why or why not?