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'.

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
a

Problem: a car gets 60 kilometers per gallon of gasoline . how many gallons of gasoline would the car need to travel 170 kilometers ?
Options: a ) 3.5 gallons , b ) 2.37 gallons , c ) 5.7 gallons , d ) 4.25 gallons , e ) 2.83 gallons
e

Problem: a train covers a distance of 20 km in 20 min . if it takes 9 sec to pass a telegraph post , then the length of the train is ?
Options: a ) 150 m , b ) 200 m , c ) 120 m , d ) 225 m , e ) 160 m
a