2019 AMC 10B Problem 1

Below is the professionally curated solution for Problem 1 of the 2019 AMC 10B, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2019 AMC 10B solutions, or check the answer key.

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Concepts:fractionratio and proportion

Difficulty rating: 770

1.

Alicia had two containers. The first was 56\frac{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\frac{3}{4} full of water. What is the ratio of the volume of the smaller container to the volume of the larger container?

58 \dfrac{5}{8}

45 \dfrac{4}{5}

78 \dfrac{7}{8}

910 \dfrac{9}{10}

1112 \dfrac{11}{12}

Solution:

Let the volumes of the first and second containers be FF and SS. The amount of water is both 56F\dfrac56F and 34S\dfrac34S, so 56F=34S\dfrac56F=\dfrac34S.

Thus FS=3/45/6=910\dfrac{F}{S}=\dfrac{3/4}{5/6}=\dfrac9{10}. Since the first container is smaller, the ratio of the smaller container to the larger container is 910\dfrac9{10}. Thus, D is the correct answer.

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