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Problem 241

Geometry Difficulty 1.4 Multiple choice CEMC Pascal · Canada · 2023

A rectangular prism has a volume of 12 cm312\text{ cm}^3. A new prism is formed by
doubling the length, doubling the width, and tripling the height of the
original prism. The volume of this new prism is

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Official solution

Suppose that the original prism has length ℓ\ell cm, width ww cm, and height hh cm.

Since the volume of this prism is 12 cm312\text{ cm}^3, then ℓwh=12\ell wh = 12.

The new prism has length 2ℓ2\ell cm,
width 2w2w cm, and height 3h3h cm.

The volume of this prism, in cm3\text{cm}^3, is (2l)×(2w)×(3h)=2×2×3×lwh=12×12=144(2l)\times (2w) \times (3h) = 2 \times 2 \times 3 \times lwh = 12 \times 12 = 144.

Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.