An empty rectangular tank with a base measuring 60 cm by 40 cm was already filled with 4 pai of water. Jimmy then used a hose to fill the tank with more water at a rate of 200 cm³ per minute. The water level then reached a height of 12 cm. After that, Sharon took 2 pails of water from the tank. The water level fell by 1.5 cm. (a) What was the volume of a pail of water? (b) How much time did the hose take to fill the tank up to the height of 12 cm before Sharon took the pails of water?
