Maths Olympiad Prep

Library / /55 of 241

, 2022

Geometry Difficulty 1.4 Junior Find the answer Canada

Two identical smaller cubes are stacked next to a larger cube.
Each of the two smaller cubes has a volume of 8. The combined height of
the smaller cubes equals the height of the larger cube. What is the
volume of the larger cube?

Pick one

Solution

Since $2 ×2×\times 2 \times 2 =
8$, a cube with edge length 2 has volume 8. (We note also that
83=2\sqrt[3]{8} = 2.)

Therefore, each of the cubes with volume 8 have a height of 2.

This means that the larger cube has a height of 2+2=42+2 = 4, which means that its volume is
43=4×4×4=644^3 = 4 \times 4 \times 4 = 64.

Want a route through all this instead of an archive? The track puts 2,444 problems in a working order, from Junior Challenge level to the IMO shortlist.

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