CEMC Pascal

Algebra Difficulty 1.6 Junior Find the answer

Which of the following is closest in value to 7?

Your answer

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

Solution

We note that $7=\sqrt{49}$ and that $\sqrt{40}<\sqrt{49}<\sqrt{50}<\sqrt{60}<\sqrt{70}<\sqrt{80}$ .
This means that $\sqrt{40}$ or $\sqrt{50}$ is the closest to 7 of the given choices.
Since $\sqrt{40} \approx 6.32$ and $\sqrt{50} \approx 7.07$ , then $\sqrt{50}$ is closest to 7.

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