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'.
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Question: Problem: noelle walks from point a to point b at an average speed of 6 kilometers per hour . at what speed , in kilometers per hour , must noelle walk from point b to point a so that her average speed for the entire trip is 7 kilometers per hour ? 
Options: a ) 6.75 , b ) 7 , c ) 7.25 , d ) 7.5 , e ) 8.4

Answer: e


Question: Problem: a train 441 m long can cross an electric pole in 21 sec and then find the speed of the train ? 
Options: a ) 88 kmph , b ) 89 kmph , c ) 76 kmph , d ) 16 kmph , e ) 18 kmph

Answer: c


Question: Problem: a and b can do a piece of work in 2 days . with the help of c they finish the work in 1 days . c alone can do that piece of work in ? 
Options: a ) 1.5 days , b ) 4 days , c ) 3 days , d ) 1 day , e ) 2 days

Answer:
e