Three men, four women and six children can complete a work in 9 days. A women does double the work a man does and a child does half the work a man does. How many women alone can complete this work in 9 days?

Correct Answer: 7

Given (3 Men + 4 Women + 6 Children) -----> 9 days

But W = 2M and C = M/2

Now, convert Men and Children into Women by

3W2 + 4W + 6W4=> 32 + 4 + 32 = 7 Women 

Therefore, 7 women alone can complete this work in 9 days.