By , 8 months ago

4M can do a work in 12 days 
Let a denotes the work done by one man in one day
   4a x 12  =  1  ( Let 1 denotes the total work)
    a = 1/48 
Similarly 6 women can do the same work in 12 days
Let b denotes the work done by one woman in one day
 6b x 12 = 1
  b = 1/72
Now 4men and 12 women are working together
 Let the number of days required = n
  n ( 4 x a + 12 x b) = 1
  n ( 4 x 1/48 + 12 x 1/72) = 1
  n ( 1/12 + 1/6) = 1
 n /4 = 1
   n = 4 days