A pipe can empty 1/4th of a cistern in 12mins. In 8 mins, what part of the cistern will be empty?  Choose one:
A) 2 / 3	B) 3 / 7	C) 4 / 9	D) 1 / 6	E) 4 / 7

Rationale: "1 / 4 - - - - 12 ? - - - - - 8 = = > 1 / 6 d"
Answer: D