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Algebra Difficulty 1.4 Junior Find the answer Canada

Square $WXYZ$ is divided into
100 small identical squares. Some small squares are shaded and some are
unshaded, as shown.

How many more of the small squares need to be shaded so that 75% of
the area of $WXYZ$ is shaded?

Pick one

Solution

Of the 100 small identical squares, 28 are presently unshaded,
and so $100-28=72$ are shaded.

So that 75% of the area of $WXYZ$ is
shaded, 75 of the 100 small squares must be shaded.

Therefore, $75-72=3$ more of the
small squares must be shaded.

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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.