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Three students work part-time mowing lawns. Experienced student A can cut the grass on one lawn in 12 minutes. Strong student B can mow one in 18 minutes. And lazy student C takes 36 minutes to finish mowing a lawn.
How long would it take them if they worked together to cut a single lawn?
Try working it out again.
You're sharp! Six minutes is correct.
Calculate how much of a lawn each can mow in one minute. Student A mows one twelfth, student B one eighteenth, and student C one thirty-sixth of a lawn in one minute.
Adding these fractions together with the highest denominator makes 6/36 or 1/6. Therefore, if they can mow a sixth of a lawn in one minute, they will take just six minutes to mow a whole lawn!
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