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Algebra Difficulty 1.2 Junior Find the answer Canada

Yihana walks for 10 minutes. A graph of her elevation in metres
versus time in minutes is shown.

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A broken line graph entitled Yihana’s Walk. The horizontal axis is
Time in minutes and the vertical axis is Elevation in metres. The five line segments in the graph are as follows:

$(0,0)$ to $(3,4)$ ,
$(3,4)$ to $(5,4)$ ,
$(5,4)$ to $(6,2)$ ,
$(6,2)$ to $(8,2)$ , and
$(8,2)$ to $(10,10)$ .

The length of time for which she was walking uphill is

Pick one

Solution

Yihana is walking uphill exactly when the graph is increasing
(that is, when the slope of the segment of the graph is positive).

This is between 0 and 3 minutes and between 8 and 10 minutes, which
correspond to lengths of time of 3 minutes and 2 minutes in these two
cases, for a total of 5 minutes.

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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.