Marked price of an item is Rs 900. On purchase of 2 items discount is 6%, on purchase of 3 items discount is 12%. Rajani buys 5 items, what is the effective discount?
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?