Question 632095
Sally can paint a room in 3 hours while it takes Steve 4 hours to paint the
same room. How long would it take them to paint the room if they worked
together?
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The LCM of 3 hours and 4 hours is 12 hours.  If they worked together for 12
hours Sally would paint 4 rooms while Steve would paint 3 rooms.  So together
they can paint 7 rooms in 12 hours, so they could paint 1 room in 7/12 hours
or 35 minutes.
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