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Let x = "how many minutes would be needed for 10 frogs to be able to eat 20 bugs".
The rate of eating is in the first case, in terms of bugs per frog per minute.
In the second case, the rate of eating is .
These rates are assumed to be equal, so you get a proportion
= , or
= .
From the last proportion,
x = 5*2 = 10.
ANSWER. 10 minutes.
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