if 12 men or 20 women can do a piece of work in 27 days , then in how many days can 9 men and 12 women together do the work ?
"c 20 days given that 12 m = 20 w = > 3 m = 5 w 9 men + 12 women = 15 women + 12 women = 27 women 20 women can do the work in 27 days . so , 27 women can do it in ( 20 * 27 ) / 27 = 20 days ."
inverse(add(divide(9, multiply(12, 27)), divide(12, multiply(20, 27))))