Question 382325
Let x=number of fences that 7 painters can paint in 5 hours (35 painter-hours) 
It takes 9 (3*3) painter-hours to paint six fences
So, it takes 1 painter-hour to paint 6/9=2/3 of a fence
Now we can set up a ratio:
one painter-hour is to 2/3 fence as 35 painter-hours is to x fences or:
1/(2/3)=35/x simplify
3/2=35/x
3x=70
x=70/3= 23 1/3 fences
Hope this helps---ptaylor