Saturday, October 16, 2010

Tom, working alone, can paint a room in 6 hours. Peter and John, working independently

Tom, working alone, can paint a room in 6 hours. Peter and John, working independently, can paint the same room in 3 hours and 2 hours, respectively. Tom starts painting the room and works on his own for one hour. He is then joined by Peter and they work together for an hour. Finally, John joins them and the three of them work together to finish the room, each one working at his respective rate. What fraction of the whole job was done by Peter?










let X = amount of time in hours for Tom, Peter, and John to complete the job

1/6 + (1/6 + 1/3) + (1/6 + 1/3 + 1/2)*X = 1

X = 1/3

Total work done by Peter:

1/3 + (1/3)*(1/3) = 4/9

ANSWER: 4/9

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