The average price of four pairs of shoes are $50 and three of those pairs are $35, $40 and $55, then what is the price of the fourth pair of shoes?

Afitness center has 2 membership plans one has a low dollar sign up fee of 15 dollars and costs 38 dollars per month to join. a second plan has a higher sign up fee of 78 dollars but a lower monthly fee of 31 dollars for what number of days of the month is the coat the same