Abox contains five keys, only one of which will open a lock. keys are randomly selected and tried, one at a time, until the lock is opened (keys that do not work are discarded before another is tried). let y be the number of the trial on which the lock is opened. a find the probability function for y . b give the corresponding distribution function. c what is p(y < 3)? p(y ≤ 3)? p(y = 3)? d if y is a continuous random variable, we argued that, for all −[infinity] < a < [infinity], p(y = a) = 0. do any of your answers in part (c) contradict this claim? why?