Let a and b be rational the difference between a and b is sometimes rational always rational or never rational

Peaches cost $4.29 per pound. find the cost of two and a quarter pounds of peaches.

Giuseppi's pizza had orders for $931.00 of pizzas. the prices were $21 for a large pizza, 514 for a medium pizza, and $7 for a small pizza. the number of large pizzas was two less than four times the number of medium pizzas. thenumber of small pizzas was three more than three times the number of medium pizzas. how many of each size of pizza were ordered?

Prove that quadrilateral is a rhombus.