A cistern has three pipes, A, B and C. The pipes A and B can fill it in 8and 16 hours respectively and C can empty it in 12 hours. If the pipes are opened in order at 1, 2 and 3 A.M. When will the cistern be empty?	Select the correct option:
A) 6 AM
B) 7 AM
C) 8 AM
D) 5 AM
E) 4 AM
1 to 2 = 1/8   2 to 3 = 1/8 + 1/16 = 3/16   6 AMfter 3 6 AMM = 1/8 + 1/16 - 1/12 = 5/48   1/8 + 3/16 = 5/16   1 h ---- 5/48   ? ----- 5/16   3hours ==&gt; 6 6 AMM   6 AMnswer:6 AM
<result>A</result>
A cistern has three pipes, A, B and C. The pipes A and B can fill it in 8and 16 hours respectively and C can empty it in 12 hours. If the pipes are opened in order at 1, 2 and 3 A.M. When will the cistern be empty?