Anvi and Vaishnav started a business with the investment of Rs. 4800 and Rs. P respectively. After 6 months and 4 days Anvi left the business and Vaishnav invested Rs. 300 more. After 2 months and 3 days from the time at which Anvi left, Madhu joined the business by invested half of the amount invested by Vaishnav. If the annual profit is Rs. 1600 and the share of Madhu is Rs. 200. Find the approximate value of P.