There are 100 million litres of fluoridated water in the reservoir containing a city\'s water supply, and the water contains 700 kg of fluoride. To decrease the fluoride content, fresh water runs into the reservoir at the rate of 3 million litres per day, and the mixture of water and fluoride, kept uniform, runs-out of the reservoir at the same rate. How many kilograms of fluoride are in the reservoir 60 days after the pure water started to flow into the reservoir?