A. 2 hrs 15 min
B. 4 hrs 24 min
C. 5 hrs
D. 3 hrs
Explanation:
1/4 + 1/5 = 9/20
20/9 = 2 2/9
9/20 * 2 = 9/10 —- 4 hours
WR = 1 – 9/10 = 1/10
1 h —- 1/4
? —– 1/10
2/5 * 60 = 24 = 4 hrs 24 min
Related Mcqs:
- Two pipes can separately fill a tank in 20 and 30 hours respectively. Both the pipes are opened to fill the tank but when the tank is full, a leak develops in the tank through which one-third of water supplied by both the pipes goes out. What is the total time taken to fill the tank?
A. 18 hrs
B. 16 hrs
C. 15 hrs
D. 12 hrs - Three pipes A, B and C can fill a tank in 6 hours. After working at it together for 2 hours. C is closed A and B can fill the remaining par in 7 hours. The number of hours taken by C alone to fill the tank is?
A. 10
B. 12
C. 14
D. 16 - A tank is filled by three pipes with uniform flow. The first two pipes operating simultaneously fill the tank in the same during which the tank is filled by the third pipe alone. The second pipe fills the tank 5 hours faster than the first pipe and 4 hours slower than the third pipe. The time required by the first pipe is?
A. 6 hrs
B. 10 hrs
C. 15 hrs
D. 30 hrs - Two pipes A and B can separately fill a tank in 2 minutes and 15 minutes respectively. Both the pipes are opened together but 4 minutes after the start the pipe A is turned off. How much time will it take to fill the tank?
A. 9 min
B. 10 min
C. 11 min
D. 12 min - Two pipes A and B can fill a tank in 15 min and 20 min respectively. Both the pipes are opened together but after 4 min, pipe A is turned off. What is the total time required to fill the tank?
A. 10 min 20 sec
B. 11 min 45 sec
C. 12 min 30 sec
D. 14 min 40 sec - Two pipes can fill a tank in 18 minutes and 15 minutes. An outlet pipe can empty the tank in 45 minutes. If all the pipes are opened when the tank is empty, then how many minutes will it take to fill the tank?
A. 12
B. 13
C. 11
D. 10 - Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full is_______?
A. 6 hrs
B. 6 2/3 hrs
C. 7 hrs
D. 7 1/2 hrs - Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full in_________?
A. 6 hours
B. 6 2/3 hours
C. 7 hours
D. 7 1/2 hours - Two pipes can fill a tank in 20 and 24 minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in 15 minutes. The capacity of the tank is?
A. 60 gallons
B. 100 gallons
C. 120 gallons
D. 180 gallons - Three pipes A, B and C can fill a tank from empty to full in 30 minutes, 20 minutes and 10 minutes respectively. When the tank is empty, all the three pipes are opened. A, B and C discharge chemical solutions P, Q and R respectively. What is the proportion of solution R in the liquid in the tank after 3 minutes?
A. 5/11
B. 6/11
C. 7/11
D. 8/11
