Maths Olympiad Prep

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, 2020

Algebra Difficulty 2.3 Junior Find the answer Canada

Tick marks are equally spaced along a number line with the numbers PP, QQ, RR, SS, TT, and UU labelled as shown.

Which of the following best represents the value of RR divided by the value of UU?

Pick one

Solution

Solution 1

Between 0 and 1.0, the number line is divided by tick marks (at PP, QQ, RR) into 4 equal lengths.

Thus, the distance between adjacent tick marks is 1.004=0.25\frac{1.0-0}{4}=0.25.

Since RR is the 3rd^{rd} tick mark moving right from 0, the value of RR is 3×0.25=0.753\times0.25=0.75.

Since UU is the 6th^{th} tick mark moving right from 0, the value of UU is 6×0.25=1.56\times0.25=1.5.
The value of RR divided by the value of UU equals 0.751.5=0.5\frac{0.75}{1.5}=0.5.

Solution 2

The number RR is located at the 3rd^{rd} tick mark to the right of 0.

The number UU is located at the 6th^{th} tick mark to the right of 0.

The tick marks are equally spaced along the number line, and so the value of RR must be half the value of UU (since 3 is half of 6).
The value of RR divided by the value of UU equals 12\frac12 or 0.5.

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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.