Question 608078
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi
Tom in 12 hours...His friend Brad could paint the set in 8 hours
Let x represent time to finish the Entire set together
Per Hour KEY:
 1/12 + 1/8 = 1/x
   8x + 12x = 96
       20x = 96
         x = 4.8 hr, 
% of work w done together in 3 hr
         1/4.8 = w/3
            3 = 4.8w
            3/4.8 = .625 = w
How many more hours h will tom need to work to finish the set
 1/12 = .625/h
   h = 12(.625)= 7.5 more hours