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 pipes can fill a tank in 18 minutes and 20 minutes . an outlet pipe can empty the tank in 45 minutes . if all the pipes are opened when the tank is empty , then how many minutes will it take to fill the tank ? 
Options: a ) 1 / 15 , b ) 1 / 16 , c ) 1 / 11 , d ) 1 / 10 , e ) 1 / 12

A: e
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Q: Problem: how many seconds will a train 120 meters long take to cross a bridge 200 meters long if the speed of the train is 36 kmph ? 
Options: a ) 22 sec , b ) 32 sec , c ) 25 sec , d ) 24 sec , e ) 31 sec

A: b
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Q: Problem: the radius of the wheel of a bus is 140 cms and the speed of the bus is 66 km / h , then the r . p . m . ( revolutions per minutes ) of the wheel is 
Options: a ) 125 , b ) 250 , c ) 300 , d ) 330 , e ) none of these

A:
a
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