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Geometry and Trigonometry / Area and volume Difficulty: Hard

Right rectangular prism X is similar to right rectangular prism Y. The surface area of right rectangular prism X is 58 square centimeters cm2, and the surface area of right rectangular prism Y is 1,450 cm2. The volume of right rectangular prism Y is 1,250 cubic centimeters cm3. What is the sum of the volumes, in cm3, of right rectangular prism X and right rectangular prism Y?

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Explanation

The correct answer is 1,260 . Since it's given that prisms X and Y are similar, all the linear measurements of prism Y are k times the respective linear measurements of prism X, where k is a positive constant. Therefore, the surface area of prism Y is k 2 times the surface area of prism X and the volume of prism Y is k 3 times the volume of prism X. It's given that the surface area of prism Y is 1,450 cm2, and the surface area of prism X is 58 cm2, which implies that 1,450 = 58 k 2 . Dividing both sides of this equation by 58 yields 1,45058=k2, or k 2 = 25 . Since k is a positive constant, k = 5 . It's given that the volume of prism Y is 1,250 cm3. Therefore, the volume of prism X is equal to 1,250 k 3  cm3, which is equivalent to 1,25053 cm3, or 10 cm3. Thus, the sum of the volumes, in cm3, of the two prisms is 1,250+10, or 1,260 .