A cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 9 hours. If both taps are opened simultaneously, then after how much time will the cistern get filled ?

A) 4.5 hours B)5 hours C) 6.5 hours D) 7.2 hours
(Wipro Question)
Asked by Priya kumari
mahi   ans:D
7 years ago
Tarun Kumar   D
7 years ago
arunkumar   1/4-1/9=5/36=7.2
7 years ago
MANOJ   D-7.2 hours..
6 years ago
ravi madhukar   d 7.2
6 years ago
karthickeyan   7.2 hours :-)
6 years ago
Bipin   Time taken by tap A to fill the cistern=4 hrs
Work done by tap A in 1 hour = 1/4th
Time taken by tap B to empty the full cistern = 9 hours
Work done by tap B in 1 hour = -1/9th
Work done by (A + B) in 1 hour=(1/4 - 1/9)=5/36
Therefore, the tank will fill the cistern = 36/5 hours=7.2 hours.
6 years ago
janardhana   answer is "d".
5 years ago
shweta kumari   7.2
4 years ago
d.ayyappa   7.2hr
4 years ago
Nikhil R. Newhale   1/4-1/9=7.2
4 years ago

Smiley