instruction:
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'.
question:
Problem: a train 150 m long crosses a platform 130 m long in 20 sec ; find the speed of the train ? 
Options: a ) 50 , b ) 60 , c ) 55 , d ) 45 , e ) 53
answer:
a


question:
Problem: if 20 typists can type 50 letters in 30 minutes , then how many letters will 40 typists working at the same rate complete in 1 hour ? 
Options: a ) 400 , b ) 500 , c ) 350 , d ) 250 , e ) 200
answer:
a


question:
Problem: the speed of a subway train is represented by the equation z = s ^ 2 + 2 s for all situations where 0 ≤ s ≤ 7 , where z is the rate of speed in kilometers per hour and s is the time in seconds from the moment the train starts moving . in kilometers per hour , how much faster is the subway train moving after 7 seconds than it was moving after 5 seconds ? 
Options: a ) 4 , b ) 28 , c ) 15 , d ) 48 , e ) 63
answer:

b