Maths Olympiad Prep

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Algebra Difficulty 1.4 Junior Find the answer Canada

Lana participates in long jump. She completes 44 jumps and achieves the following results: 1.60 m1.60~\text{m}, 1.65 m1.65~\text{m}, 1.85 m1.85~\text{m}, 1.90 m1.90~\text{m}. What is the mean (average)
of her results?

Pick one

Solution

The mean (average) of Lana's 44 jumps is $1.60 m+1.65 m+1.85 m+1.90 m4=7 m4=1.75\$\dfrac{1.60\text{ m}+1.65\text{ m}+1.85\text{ m}+1.90\text{ m}}{4}=\dfrac{7\text{ m}}{4}=1.75\text{} m}$.

(In place of the calculation above, we may have noticed that 1.751.75 is "in the middle" of 1.651.65 and 1.851.85 (thus is the mean of these two
numbers), and 1.751.75 is also in the
middle of 1.601.60 and 1.901.90, and thus is the mean of the four
numbers.)

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