In a bag there are red and blues marbles in the ratio 2:7. What is the ratio of blue marbles to the total in the bag

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

Find cot x if sin x cot x csc x = √2

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?