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Algebra Difficulty 1.4 Junior Find the answer Canada

If snow falls at a rate of 1 mm every 6 minutes, then how many hours will it take for 1 m of snow to fall?

Pick one

Solutions — 2

Solution 1

Since 1 mm of snow falls every 6 minutes, then 10 mm will fall every $6\times10=60$ minutes.

Since 10 mm is 1 cm and 60 minutes is 1 hour, then 1 cm of snow will fall every 1 hour.
Since 1 cm of snow falls every 1 hour, then 100 cm will fall every $1\times100=100$ hours.

Solution 2

Since $\frac{14+1}{3+1}=\frac{15}{4}$ and $\frac{21}{4}-\frac{5}{4}-\frac{1}{4}=\frac{16}{4}-\frac{1}{4}=\frac{15}{4}$ , then answers (B) and (E) both simplify to $\frac{15}{4}$ .

Written as a mixed fraction, $\frac{15}{4}$ is equal to $3\frac{3}{4}$ .

Since $3.75=3\frac{3}{4}=3+\frac{3}{4}$ , then answers (A) and (C) both simplify to $3\frac{3}{4}$ and thus are equivalent to $\frac{15}{4}$ .

Simplifying answer (D), $\frac{5}{4}\times\frac{3}{4}=\frac{5\times3}{4\times4}=\frac{15}{16}$ .
Thus, $\frac{5}{4}\times\frac{3}{4}$ is not equal to $\frac{15}{4}$ .

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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.