Question 628119
The rate of painting for 2 painters is
( 3 houses ) / ( 40 hrs )
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Half the number of painters will take 
twice as long to paint 3 houses, so
The rate of painting for 1 painter is
( 3 houses ) / ( 80 hrs )
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5 painters can paint the same number
of houses in 1/5 the time, so
The rate of painting for 5 painters is
( 3 houses ) / ( 16 hrs )
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It will take the 5 painters twice as long
to paint twice as many houses, or
( 6 houses ) / ( 32 hrs )
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It will take the 5 painters 1/3 as long
to paint 1/3 as many houses, so
The rate of painting for 5 painters is
( 2 houses ) / ( 10 and 2/3 hrs )
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Final answer:
I takes 5 painters 10 hours and 40 minutes to paint 2 houses