Two pipes A and B can fill a tank in 36 min. and 45 min. respectively. A water pipe C can empty the tank in 30 min. First A and B are opened. After 7 min, C is also opened. In how much time, the tank is full?
A. 17 min
B. 24 min
C. 28 min
D. 39 min
Answer:D
Two pipes A and B can fill a tank in 36 min. and 45 min. respectively. A water pipe C can empty the tank in 30 min. First A and B are opened. After 7 min, C is also opened. In how much time, the tank is full?
A. 17 min B. 24 min C. 28 min D. 39 min
Explanation: Part filled in 7 min. = 7*((1/36) + (1/45)) = (7/20).