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Mickey mows 1/3 of a lawn in 10 minutes. Minnie mows 1/4 of the lawn in 6 minutes. A student claims that Minnie is mowing faster because she only worked for 6 minutes, while Mickey worked for 10 minutes. Is the students reasoning correct ?

User Ben Keil
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1 Answer

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14 votes

Mickey mows 1/3 of a lawn in 10 minutes.

So, his rate = (1/3) / 10 = 1/30 lawn/min

Minnie mows 1/4 of the lawn in 6 minutes.

So, his rate = (1/4) / 6 = 1/24 lawn/min

compare the fractions:


\begin{gathered} (1)/(30)\text{ }(1)/(24)\text{ } \\ \end{gathered}

Make the denominator are equal so, the common denominator is ( 30 x 24 = 720 )

So,


\begin{gathered} (1)/(30)=(24)/(720) \\ (1)/(24)=(30)/(720) \\ So, \\ (30)/(720)>(24)/(720) \\ So,\text{ } \\ (1)/(24)>(1)/(30) \end{gathered}

So, the rate of Minnie is faster than Mickey

This is because the rate of Minnie is greater than the rate of Mickey

So, the student reasoning is not correct

User Farrellmr
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