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'.

[EX Q]: Problem: if 20 typists can type 48 letters in 20 minutes , then how many letters will 30 typists working at the same rate complete in 1 hour ? 
Options: a ) 63 , b ) 72 , c ) 144 , d ) 216 , e ) 400
[EX A]: d

[EX Q]: Problem: a thief goes away with a santro car at a speed of 30 kmph . the theft has been discovered after half an hour and the owner sets off in a bike at 60 kmph when will the owner over take the thief from the start ? 
Options: a ) 1 hours , b ) 2 hours , c ) 2 / 3 hours , d ) 1 / 3 hours , e ) 2 / 5 hours
[EX A]: a

[EX Q]: Problem: trains a and b start simultaneously from stations 450 miles apart , and travel the same route toward each other on adjacent parallel tracks . if train a and train b travel at a constant rate of 50 miles per hour and 50 miles per hour , respectively , how many miles will train a have traveled when the trains pass each other , to the nearest mile ? 
Options: a ) 112 , b ) 133 , c ) 150 , d ) 167 , e ) 225
[EX A]:
e