Help please....

At a certain pizza parlor, 60% of the customers order a pizza containing onions, 37% of the customers order a pizza containing sausage, and 66% order a pizza containing onions or sausage (or both). Find the probability that a customer chosen at random will order a pizza containing both onions and sausage. Write your answer as a decimal (not as a percentage). (If necessary, consult a list of formulas.)