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, 2017

Geometry Difficulty 2.4 Junior Find the answer Canada

In the diagram shown, David begins at $A$ and walks in a straight line to $C$ , and then walks in a straight line from $C$ to $B$ . Cindy also begins at $A$ and walks in a straight line to $B$ .

How much farther does David walk than Cindy?

Pick one

Solution

If puzzles are bought individually for $10 each, then 6 puzzles will cost$ $\$10\times6=\$60\$.$

Since the cost for a box of 6 puzzles is $50, it is less expensive to buy puzzles by the box than it is to buy them individually.

Buying 4 boxes of 6 puzzles gives the customer $4\times6=24$ puzzles and the cost is $4\times\$50=\$200$ .

Buying one additional puzzle for 10 gives the customer 25 puzzles at a minimum cost of \$210$.

Want a route through all this instead of an archive? The track puts 2,444 problems in a working order, from Junior Challenge level to the IMO shortlist.

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