A man purchased a car with a cash price of P 350,000. He was able to negotiate with the seller to allow him to pay only a downpayment of 20% and the balance payable in equal 48 end of the month installment at 1.5% interest per month. One the day he paid the 20th installment, he decided to pay monthly payment. How much is his monthly payment?
The downpayment is 20% of P 350,000, so the downpayment is P 350,000 x 20% = P 70,000.
The balance of the car is P 350,000 - P 70,000 = P 280,000.
The interest per month is P 280,000 x 1.5% = P 4,200.
The monthly payment is P 4,200 x 48 = P 201,600.
So, the monthly payment is P 201,600 / 48 = P 4,200. Answer: \boxed{4200}.