In the beginning of 2020, the population of three cities 'A', 'B', and 'C' was in the ratio of 4 : 5 : 6 respectively. During the year 2021, the population of respective cities increased by a percentage in the ratio of 7 : 5 : 9. In the beginning of 2021, the population of city 'C' was 27000 more than that of the beginning of the year 2020 and in the beginning of the year 2021 the ratio of the population of A : B was 108 : 125 then during the year 2020, what was the sum of the increase in the population of all the cities together?