Mohan deposit certain amount in bank saving account for 6 year which give simple interest of x% annually and invest same principle in fix deposit for 2 year which gives interest rate 10% and compounded annually, total interest he get from saving account to fix deposit in the ratio of 6 : 7, if bank provide (x + 3)% rate annually on saving account deposit, then difference of interest arise Rs.7,500 between saving account and fix deposit after respective time period, what amount he invest in fix deposit?