What is meant by the net change colum of a stock listing

Weekly wages at a certain factory are normally distributed with a mean of $400 and a standard deviation of $50. find the probability that a worker selected at random makes between $450 and $500

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?

Your friend uses c=50p to find the total cost, c, for the people, p, entering a local amusement park is the cost of admission proportional to the amount of people entering the amusement park? explain.