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: stacy has a 81 page history paper due in 3 days . how many pages per day would she have to write to finish on time ? 
Options: a ) 9 , b ) 27 , c ) 10 , d ) 8.5 , e ) 6
[EX A]: b

[EX Q]: Problem: the speed of a car is 60 km in the first hour and 30 km in the second hour . what is the average speed of the car ? 
Options: a ) 45 kmph , b ) 65 kmph , c ) 75 kmph , d ) 85 kmph , e ) 90 kmph
[EX A]: a

[EX Q]: Problem: two trains start simultaneously from opposite ends of a 175 - km route and travel toward each other on parallel tracks . train x , traveling at a constant rate , completes the 175 - km trip in 4 hours . train y , travelling at a constant rate , completes the 175 - km trip in 3 hours . how many kilometers had train x traveled when it met train y ? 
Options: a ) 66 , b ) 69 , c ) 72 , d ) 75 , e ) 78
[EX A]:
d