If it takes a tub 4 minutes to drain 5/7 of its content, how much more time will it take for the tub to be empty? Choose the correct choice from the following answers:
A) 48 seconds  B) 1 minute, 12 seconds  C) 1 minute, 36 seconds  D) 2 minutes, 14 seconds  E) 4 minutes, 12 seconds
If 5/7 of tub's content is drained 2/7 th of tub still needs to be drained.   If it takes 4 minutes to drain 5/7 th of tub it takes 4*(7/5) minutes to drain the entire tub and 4*(7/5)*(2/7) min to drain 2/7 th of the tub which is 8/5 minutes or 1 3/5 minutes or 1 minute 36 seconds   So answer is 1 minute, 36 seconds
<result>C</result>
If it takes a tub 4 minutes to drain 5/7 of its content, how much more time will it take for the tub to be empty?