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Right rectangular prism X is similar to right rectangular prism Y. The surface area of right rectangular prism X is , and the surface area of right rectangular prism Y is . The volume of right rectangular prism Y is . What is the sum of the volumes, , of right rectangular prism X and right rectangular prism Y?
Explanation
The correct answer is . Since it's given that prisms X and Y are similar, all the linear measurements of prism Y are times the respective linear measurements of prism X, where is a positive constant. Therefore, the surface area of prism Y is times the surface area of prism X and the volume of prism Y is times the volume of prism X. It's given that the surface area of prism Y is , and the surface area of prism X is , which implies that . Dividing both sides of this equation by yields , or . Since is a positive constant, . It's given that the volume of prism Y is . Therefore, the volume of prism X is equal to , which is equivalent to , or . Thus, the sum of the volumes, in , of the two prisms is , or .