The development of public housing in a city is under study. It is given that the total floor area of all public housing flats at the end of the 1st year is
9×106 m2 and in subsequent years, the total floor area of public housing flats built each year is
r% of the total floor area of all public housing flats at the end of the previous year, where
r is a constant, and the total floor area of public housing flats pulled down each year is
3×105 m2. It is found that the total floor area of all public housing flats at the end of the 3rd year is
1.026×107 m2.