2019 AMC 12B Problem 1

Attempt Problem 1 of the 2019 AMC 12B below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2019 AMC 12B solutions, or check the answer key.

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1.

Alicia had two containers. The first was 56\dfrac{5}{6} full of water and the second was empty. She poured all the water from the first container into the second container, at which point the second container was 34\dfrac{3}{4} full of water. What is the ratio of the volume of the first container to the volume of the second container?

58\dfrac{5}{8}

45\dfrac{4}{5}

78\dfrac{7}{8}

910\dfrac{9}{10}

1112\dfrac{11}{12}

Answer: D
Concepts:ratio and proportionfraction
Difficulty rating: 880
Solution:

The volume of water is the same before and after, so 56V1=34V2.\dfrac{5}{6}V_1=\dfrac{3}{4}V_2.

Then V1V2=3/45/6=3465=910. \dfrac{V_1}{V_2}=\dfrac{3/4}{5/6}=\dfrac{3}{4}\cdot\dfrac{6}{5}=\dfrac{9}{10}.

Thus, D is the correct answer.

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