Three fourths of the offspring of two fruit flies have short wings, while the rest have wild-type wings . In a batch of offspring from those

Question

Three fourths of the offspring of two fruit flies have short wings, while the rest have wild-type wings . In a batch of offspring from those two flies, 100 have wild-type wings. How many of the flies have short wings?

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Thạch Thảo 2 weeks 2021-07-19T02:37:43+00:00 1 Answers 1 views 0

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    2021-07-19T02:39:02+00:00

    Answer:

    300

    Step-by-step explanation:

    If three-fourths of the offspring of two fruit flies have short wings and the rest have wild-type wings, then 1-\frac{3}{4}=\frac{1}{4} of the offspring must have wild-type wings. This means that the number of offspring that have short wings must be \frac{3/4}{1/4}=\frac{3}{4}\cdot \frac{4}{1}=3 times larger than the number of offspring that have wild-type wings. Since there are 100 offspring who have wild-type wings, there must be 100\cdot 3=\boxed{300} that have short wings.

    Alternative:

    If three-fourths of the offspring of two fruit flies have short wings and the rest have wild-type wings, then 1-\frac{3}{4}=\frac{1}{4} of the offspring must have wild-type wings. Therefore, 100 represents one-fourth of the total number of offspring, meaning there must be 100\cdot 4=400 offspring total. Thus, there are 400-100=\boxed{300} offspring with short wings.

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