The three painters have painted bridge. The first would work done in 5 days, the second in 6 days, and the third in 7.5 days. How long will the bridge work if they work together?
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Why the third fraction 1/7.5 when it is supposed to be 1/7?
Yes, there was bug, but now is corrected. Thank you
To solve this example are needed these knowledge from mathematics:
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