The entire contents of a full sack of flour can be used to make 15 cupcakes and 10 pizzas. The same full sack of flour can be used to make 7 cupcakes and 14 pizzas. If a full sack of flour is used to make only pizzas, how many pizzas can be made?	Answers:  A) 10  B) 21 1/2  C) 18 3/4  D) 19  E) 19 1/4
15x+10y=7x+14y   x=1/2y. Answer 21 1/2
<result>B</result>
The entire contents of a full sack of flour can be used to make 15 cupcakes and 10 pizzas. The same full sack of flour can be used to make 7 cupcakes and 14 pizzas. If a full sack of flour is used to make only pizzas, how many pizzas can be made?