1. A man bought a house and lot worth P300,000 in a subdivision in Metro Manila. The annual amortization for the house and lot is P34,200. Determine the rate of interest he was charged by the subdivision owners.

2. A man purchased a computer worth P15,000 with interest at 5% payable semi-annually. He signed a contract to pay P5,000 and the balance, principal and interest included, by equal payments at the end of each 6 months fot 10 years. At the end of 4 years this computer was sold to yield the investor 7% payable semi-annually. Find the price he was paid.

3. A mechanical engineer designed a mechanical device costing P20,000. Maintenance will cost P1,000 each year. The device will generate revenue of P5,000 each year for 5 years, after which the salvage value is expected to be P7,000. Draw the cash flow diagram