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:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

Captain umaima has a ship, the h. m.s. khan. the ship is two furlongs from the dread pirate nadia and her merciless band of thieves. the captain has probability 3/7 of hitting the pirate ship. the pirate only has one good eye, so she hits the captain's ship with probability 2/5. if both fire their cannons at the same time, what is the probability that the captain hits the pirate ship, but the pirate misses.