A contractor undertook to make 20 km of roadway in 48 weeks. In 28 weeks, 8 km was completed by 120 men working 12 hours a day. The men then agreed to work 3 hour a day overtime and some women were engaged to assist them, the work was finished in the stipulated time. How many women were employed, if the work of 8 men is equal to that of 5 women.