In a class of 21 students, each scored differently. P's rank from the bottom is 9th, while Q's rank from the top is also 9th. How many students are ranked between Q and P?
If A bought an item for Rs 384 and sold it for Rs 576 and B bought another item for Rs 1,254 and sold it for Rs 1,672. What is the ratio of gain % of A to gain % of B?