In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[Q]: Problem: two taps a and b can fill a cistern in 12 minutes and 18 minutes respectively . they are turned on at the same time . if the tap a is turned off after 4 minutes , how long will tap b take to fill the rest of the cistern ? 
Options: a ) 8 min . , b ) 9 min . , c ) 10 min . , d ) 7 min . , e ) none of these
[A]: a


[Q]: Problem: a train speeds past a pole in 15 sec and a platform 100 m long in 25 sec , its length is ? 
Options: a ) 158 m , b ) 150 m , c ) 110 m , d ) 130 m , e ) 157 m
[A]: b


[Q]: Problem: the distance from steve ' s house to work is 35 km . on the way back steve drives twice as fast as he did on the way to work . altogether , steve is spending 6 hours a day on the roads . what is steve ' s speed on the way back from work ? 
Options: a ) 5 . , b ) 10 . , c ) 14 . , d ) 15 . , e ) 17.5
[A]:
e