Question

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A washing machine is filling up with water at a constant rate. The rate is of a gallon in 5 of a minute. Don calculated the
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unit rate to be 20 of a gallon per minute. What did he do wrong?
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O He added to 5 instead of multiplying 4 by 5.
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O He divided by 5 instead of multiplying 4 by 5.
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O He added 4 to 5 instead of dividing 4 by 5.
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He multiplied by 5 instead of dividing 4 by 5.

Answer 1

Don calculated the unit rate incorrectly by multiplying when he should have divided the given fraction. The correct unit rate should be found by dividing ¼ of a gallon by ¾ of a minute, which is equivalent to multiplying by the reciprocal of ¾ minute.

Step-by-step explanation:

The student's question is about calculating the unit rate of a quantity measured in different units of volume. When Don calculated the unit rate of a washing machine filling up with water at a constant rate of ¼ of a gallon in ¾ of a minute, he erroneously determined it to be 20 gallons per minute.

However, to find the correct unit rate of gallons per minute, we need to set up a ratio that compares gallons to minutes. We are given ¼ of a gallon in ¾ of a minute, and we need to find out how many gallons would fill in one full minute. To do this, we would divide the amount of gallons (¼) by the fraction of the minute (¾), which is equivalent to multiplying by its reciprocal.

Therefore, the correct method is: ¼ of a gallon ÷ ¾ of a minute which is the same as ¼ of a gallon × ⅔ of a minute. The student or Don in the provided situation may have mistakenly multiplied by 5 instead of dividing the fraction, leading to an incorrect unit rate.