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: at a speed of 50 miles per hour , a certain car uses 1 gallon of gasoline every 30 miles . if the car starts with a full 10 gallon tank of gasoline and travels for 5 hours at 50 miles per hour , the amount of gasoline used would be what fraction of a full tank ? 
Options: a ) 3 / 25 , b ) 5 / 6 , c ) 7 / 12 , d ) 2 / 3 , e ) 25 / 36
[A]: b


[Q]: Problem: how long does a train 165 meters long running at the rate of 54 kmph take to cross a bridge 660 meters in length ? 
Options: a ) 55 sec , b ) 40 sec , c ) 45 sec , d ) 30 sec , e ) 35 sec
[A]: a


[Q]: Problem: a water tank is one - fifth full . pipe a can fill a tank in 10 minutes and pipe b can empty it in 6 minutes . if both the pipes are open , how many minutes will it take to empty or fill the tank completely ? 
Options: a ) 3 , b ) 6 , c ) 9 , d ) 12 , e ) 15
[A]:
a