A tap can fill a tank in 6 hours. After half the tank is filled three more similar taps are opened. What is the total time taken to fill the tank completely?  Pick.
A) 3hrs25 min	B) 3hrs45 min	C) 3hrs75 min	D) 3hrs49 min	E) 3hrs25 min
Time taken by one tap to fill the tank = 3 hrs.   Part filled by the taps in 1 hour = 4 * 1/6 = 2/3   Remaining part = 1 - 1/2 = 1/2   2/3 : 1/2 :: 1 : x   x = 1/2 * 1 * 3/2 = 3/4 hrs. i.e., 45 min   So, total time taken = 3 hrs 45 min.   Answer: 3hrs45 min
<result>B</result>
A tap can fill a tank in 6 hours. After half the tank is filled three more similar taps are opened. What is the total time taken to fill the tank completely?