Maths Olympiad Prep

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, 2018

Algebra Difficulty 1.2 Junior Find the answer Canada

If there is no tax, which of the following costs more than $18 to purchase?

Five 1 items and five 2 items\text{Five 1 items and five 2 items}
Nine 1 items and four 2 items\text{Nine 1 items and four 2 items}
Nine 1 items and five 2 items\text{Nine 1 items and five 2 items}
Two 1 items and six 2 items\text{Two 1 items and six 2 items}
Sixteen 1 items and no 2 items\text{Sixteen 1 items and no 2 items}

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

Solution

The cost of nine 1itemsandfive1 items and five 2 items is (9×$1)+(5×$2)(9\times\$1)+(5\times\$2), which is $9+$10\$9+\$10 or $19.

The correct answer is (C).

(We may check that each of the remaining four answers gives a cost that is less than $18.)

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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.