A tank is filled in eight hours by three pipes A, B and C. Pipe A is twice as fast as pipe B, and B is twice as fast as C. How much time will pipe B alone take to fill the tank?	Select
A) 17 hours	B) 28 hours	C) 19 hours	D) 14 hours	E) 14 hours
1/A + 1/B + 1/C = 1/8 (Given)   Also given that A = 2B and B = 2C   =&gt; 1/2B + 1/B + 2/B = 1/8   =&gt; (1 + 2 + 4)/2B = 1/8   =&gt; 2B/7 = 8   =&gt; B = 28 hours.   Answer: 28 hours
<result>B</result>
A tank is filled in eight hours by three pipes A, B and C. Pipe A is twice as fast as pipe B, and B is twice as fast as C. How much time will pipe B alone take to fill the tank?