A pipe can fill a cistern in 77 minutes. Find the time in which 1/11 part of the cistern will be filled?  Choose one:
A) 5 min
B) 2 min
C) 3 min
D) 1 min
E) 7 min

Rationale: "full cistern filled in = 77 minutes 1 / 11 part filled in = 77 * 1 / 11 = 7 minutes answer is e"
Answer: E