A cistern can be filled by a tap in 2 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled ?
Pick:
A) 2.57 hrs
B) 5 hrs
C) 6.57 hrs
D) 7.2 hrs
E) 9.27 hrs
Net part filled in 1 hour= 1/2 -1/9= 7/18   Therefore the cistern will be filled in 18/7 hours or 2.57 hours.   2.57 hrsNSWER:2.57 hrs
<result>A</result>
A cistern can be filled by a tap in 2 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled ?