A cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 8 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled? Choices
A) 2.9 hrs	B) 8.9 hrs	C) 2.9 hrs	D) 7.2 hrs	E) 8 hrs
Net part filled in 1 hour = (1/4 - 1/8)   = 1/8   The cistern will be filled in 8 hrs i.e., 8 hrs.   Answer:8 hrs
<result>E</result>
A cistern can be filled by a tap in 4 hours while it can be emptied by another tap in 8 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled?