Two pipelines A and B, respectively, can fill a tank in 20 and 30 minutes. How long will it take to fill the tank if both hoses are used together?
A. 12 min
B. 15 min
C. 25 min
D. 50 min
Answer:A
Two pipelines A and B, respectively, can fill a tank in 20 and 30 minutes. How long will it take to fill the tank if both hoses are used together?
A. 12 min B. 15 min C. 25 min D. 50 min
Explanation: A filled 1/20 of the part in 1 minute.B filled 1/30 of the part in 1 minute.Part filled in 1 minute by (A + B) = 1/20 + 1/30 = 1/12In 12 minutes, both pipes may fill the tank.