I need correct answers to the following questions

Explain or state briefly the rule or reason for your answer.

1. A and B entered into a contract not specifically provided in the

Civil Code. Is the contract valid and binding?

2. S (seller) and B (buyer) entered into a contract of sale. It was

agreed that the price shall be determined by T, a third person. Can

S and B refuse to be bound by T's determination of the price if he

does not agree with the amount thereof?

3. D owes C P 20,000.00. Both are house painters. It was agreed

that D instead of paying C, will paint the house of E to which E

expressed his conformity to C whose service as painter was

previously contracted by E. Has B the right to enforce the

stipulation between C and D?

4. X made an office desk for Y. X told Y that the latter may pay

whatever amount he would like to pay for it. When the desk was

finished Y offered to pay P 2,000.00 but instead demanded

P3,000.00, its fair value. Is X entitled to P 3,000.00?

PROBLEMS

Explain or state briefly the rule or reason for your answer.

1. S sold his house to B believing that B was C. Can S legally

withdraw from the contract on the ground of mistake?

2. S agreed to deliver to B 500 cavans of rice at P 600 per cavan. S

delivered only 490 cavans deliberately misrepresenting that the

delivery consisted of 500 cavans. Can B ask the court to annul the

contract on the ground of fraud?

3. S has several pigs. Under a contract of sale, S binds himself to

deliver a pig to a B for P3,000.00 if the pig has a weight of a at

least 30 kilos. State the binding effect of the sale?

4. S sold to B a specific parcel of land for P 500,000.00 B failed to

pay. Has C the right to have the sale declared void by the court on

the ground of absence of cause for non-payment of the price?

5. S sold B his car worth P 250,000.00 for only P 200,000. There is

no question that the purchase price is grossly inadequate. Has S

the right to have the sale annulled?