A company awards at the end of the year 90 employers for their excellence giving them totally 4000 shares. Every man gets as many shares as the number of women awarded and every woman gets as many shares as the number of men awarded. Find the number of these men and women.
A boat follows the stream of a river that has length 240 km. On its way back the speed of the boat decreases over km/h and the trip lasts 2 hours more. In how many hours did the boat go down the river?