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07 Sep 2020, 02:17
Kudos
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B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
69% (02:56) correct
31%
(03:17)
wrong
based on 222
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A tank can be filled by Pipe1 in 7 hours and by Pipe2 in 5 hours. There is a waste pipe which is kept open when Pipe2 is working; the tank then takes 8 hours 30 minutes to fill. What is the time taken to fill the tank if all the three pipes are working?
A)3 hours 20 minutes
B)3 hours 50 minutes
C)4 hours 15 minutes
D)4 hours 50 minutes
E)5 hours 30 minutes
A)3 hours 20 minutes
B)3 hours 50 minutes
C)4 hours 15 minutes
D)4 hours 50 minutes
E)5 hours 30 minutes
07 Sep 2020, 06:40
Kudos
Bookmarks
Time taken by Pipe 1 to fill the tank = 7 hours
Amount filled in 1 hour = \(\frac{1}{7}\)
Time taken by Pipe 2 and the waste pipe to fill the tank = 8.5 hours
Amount filled in 1 hour = \(\frac{1}{8.5} = \frac{10}{85} = \frac{2}{17}\)
Net work done in 1 hour when all are working = \(\frac{1}{7} + \frac{2}{17} = \frac{17 \space + \space 14}{119} = \frac{31}{119}\)
Therefore time taken to fill the tank = \(\frac{119}{31} = 3.84\) hours
To convert 0.84 hours in minutes, we multiply by 60 = 60 * 0.84 = 50.4 minutes
Total time taken is 3 hours and 50 minutes.
Option B
Arun Kumar
Amount filled in 1 hour = \(\frac{1}{7}\)
Time taken by Pipe 2 and the waste pipe to fill the tank = 8.5 hours
Amount filled in 1 hour = \(\frac{1}{8.5} = \frac{10}{85} = \frac{2}{17}\)
Net work done in 1 hour when all are working = \(\frac{1}{7} + \frac{2}{17} = \frac{17 \space + \space 14}{119} = \frac{31}{119}\)
Therefore time taken to fill the tank = \(\frac{119}{31} = 3.84\) hours
To convert 0.84 hours in minutes, we multiply by 60 = 60 * 0.84 = 50.4 minutes
Total time taken is 3 hours and 50 minutes.
Option B
Arun Kumar
General Discussion
yashikaaggarwal
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07 Sep 2020, 04:02
Kudos
Bookmarks
Let the tank capacity = 595 liters
A Pipe fill tank in 7 hours
so per hour speed = 85liter/hour
B Pipe fill tank in 5 hours
so per hour speed = 119liter/hour
The drainage pipe C and Inlet Pipe B fill tank in 8.5 hours
so they fill 595/8.5 = 70 liter / hour
B-C = 70
119-C = 70
C = 49
so C empty 49 liter per hour
A, B and C per hour working rate =
85+119-49 = 85+70 = 155 liter/hour
Working together
A,B,C can fill 595 liter tank in : 595/155 = 3.83 hours or 3 hours and 50 minutes
Answer is B
A Pipe fill tank in 7 hours
so per hour speed = 85liter/hour
B Pipe fill tank in 5 hours
so per hour speed = 119liter/hour
The drainage pipe C and Inlet Pipe B fill tank in 8.5 hours
so they fill 595/8.5 = 70 liter / hour
B-C = 70
119-C = 70
C = 49
so C empty 49 liter per hour
A, B and C per hour working rate =
85+119-49 = 85+70 = 155 liter/hour
Working together
A,B,C can fill 595 liter tank in : 595/155 = 3.83 hours or 3 hours and 50 minutes
Answer is B
