Question 950626
2000m/(90 men/20day)=1.11 m /man/day Each man digs 1.11 meters of canal per day.
To finish the contractor must dig 6 km-2km=4km in 35 days-20 days=15 days.
To dig 4 km (4000 meters)in 15 days, he must dig 4000 m/15=266.67 meters per day. At 1.11 meters per man, he needs a total of 266.67 m/1.11 m/man=241 men. He already has 90 men so he needs (241 men-90 men)=151 men.
ANSWER: The contractor needs to hire 151 more men to finish the canal on time.