A contractor agrees to lay a road 3000m long in 30 days. 50 men are employed and they work for 8 hours per day. After 20 working days, he finds that only 1200m of the road is completed. How many more men does he need to employ in order to finish the project on time if each man now works 10 hrs a day?
It will take a total of 72 men, or an to complete the remaining of the work, in 10 days, working 10 hours per day.