What is the interquartile range?

1.two more than the quotient of a number and 6 is equal to 7 use the c for the unknown number translate the sentence into an equation

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

1: 4 if the wew 35 surfboards at the beach how many were short boards?