3 men, 4 women and 6 children can complete a work in 7 days. A woman does double the work a man does and child does half the work a man does. How many women alone can complete this work in 7 days?
7
Let 1 woman`s 1 day`s work = x
Then, 1 man`s 1 day`s work =x2 and 1 child`s 1 day`work = x4
So, 3x2+4x+6x4=17
28x4=17
x = 149
1 woman alone can complete the work in 49 days
So, to complete the work in 7 days, number of women required = 497 = 7