According to a survey conducted by the National Pizza Foundation that I just now made up, out of 109 customers surveyed, 32 prefer pizzas with just pepperoni, 40 with just sausage, and 18 with only onions. Thirteen big-time carnivores like pepperoni and sausage, 10 customers prefer sausage and onions, 9 customers like pep-peroni and onions; in each case, the third item could be included as well. Seven go all out, ordering all three. (a) How many customers prefer pepperoni, or sausage, or pepperoni and sausage with no onions?
(b) What about sausage, or onions, or sausage and onions with no pepperoni?
(c) How many go the boring route—none of those toppings?