Explanation:
So he sold 33.
29 had pepperoni and of these 29, 15 had also sausage. SO first, to find out how many pepperoni pizzas only he sold you have to substract.
29-15= 14
14pepperoni pizzas
15 pepperoni and sausage pizzas.
Now we add 14 + 15 = 29
Now we do 33-29= 4
So the final answer to the question is:
10 pizzas more