If the population of a town increases by 25% in the first year and increases by 36% in the second year, then what is the average rate (in percentage)of increase in the population?
In a bag the ratio of red balls to green balls is 4 : 9. If 6 more green balls were added to the bag, the ratio of red balls to green balls would become 1 : 3. How many red balls are there in the bag?