Business Math - Give the Correct Answer and Show Complete Solution. (See comments also. Thanks)

1. Find the present value and amount of an annuity of P2,500 payable at the beginning of each 3 months whose term is 7 years and money's worth is at 6.5% interest rate, compounded quarterly.
2. Russel owes Cathy a certain amount of money and promises to settle her obligation by paying P4,500 at the beginning of each 3 months for 4 years and 6 months with interest at 12% converted quarterly. Find how much the loan is.
3. Mrs. Coronacion wishes her son Dennis to receive a certain amount on his 19th birthday. To realize this, Mrs. Coronacion will invest P2,500 at the beginning of each year after Dennis turns 7. If money earns interest at 5% compounded annually, how much will Dennis receive at the age of 19?