The opening prices per share of four similar stocks X1, X2, X3, X4 are independent random variables, each with density function e'lz'al if 2: 2 6 at} _ {0 else I a} On a particular trading day, you are going to buy shares of the stock that is the cheapest. Find the probability density function for the price per share Y that you will have to pay. 1 y} = ate-\"5'43, y > 6 y} = gel6'5\"\"), y > 4 f(y) = lilo\"943), y > 5