Question 851246
21 days * 8 hours = 168.  Multiply that by 15 men to get 2520 man-hours for this project.
The women in this equation work at the rate of 2/3 of the men.  They'll need to have 2520 * 3/2 man-hours to equal the men.  2520*3/2= 3780 man-hours.  Divide those hours among 21 women to get 3780/21 = 180.  They're only working 6 hours.  Divide 180 by 6 to get 180/6=30 days.