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Problem 600

Geometry Difficulty 2.7 Multiple choice CEMC Gauss (Grade 8) · Canada · 2014

The diagram shown consists of circles with radius 1cm and semi-circles with radius 1cm.

The total shaded area, in cm $^2$ , is

Pick one

Official solution

At Store Q, the bicycle’s regular price is $15\%$ more than the price at Store P, or $15\%$ more than $200. Since$ 15\% $of 200 is$ $\frac{15}{100}\times200=0.15\times200=30$ $, then$ 15\% $more than$ 200 is $\$200+\$30$ or $\$230$ . This bicycle is on sale at Store Q for 10% off of the regular price, $230.

Since $10\%$ of 230 is $\frac{10}{100}\times230=0.10\times230=23$ , then $10\%$ off of $230 is$ $230-$23 $or$ $207. The sale price of the bicycle at Store Q is

Figure for this problem 207.

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