Two pipes a and b separately fill in 15/2 min and 5 min respactively and third pipe c can empty of 14l/m if all the pipes are open when the cistern is full, it is emptied in 1 hr. how many litres does the cistern hold?	Choices:
A) 40	B) 30	C) 50	D) 80	E) 54
LET TOT40L W40TER IN CISTERN=X LITER   SPEED OF 40=2X/15 L/M (SPEED=LITER/TIME)   SPEED OF B=X/5 L/M   SPEED OF C=14 L/M   40CCORDING TO QUESTION   X+(X/5+2X/15)*60=60*14   X+=60*14   X=40 LITER   40NSWER:40
<result>A</result>
Two pipes a and b separately fill in 15/2 min and 5 min respactively and third pipe c can empty of 14l/m if all the pipes are open when the cistern is full, it is emptied in 1 hr. how many litres does the cistern hold?