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: a can do a piece of work 60 days . b can do work in 20 days . in how many days they will complete the work together ? 
Options: a ) 12 days , b ) 16 days , c ) 15 days , d ) 17 days , e ) 18 days
[EX A]: c

[EX Q]: Problem: two trains of equal length , running with the speeds of 60 and 90 kmph , take 50 seconds to cross each other while they are running in the same direction . what time will they take to cross each other if they are running in opposite directions ? 
Options: a ) 3.2 , b ) 2.6 , c ) 6.6 , d ) 32.2 , e ) 42.2
[EX A]: c

[EX Q]: Problem: gary ’ s gas station serves an average of 15 cars per hour on saturdays , 10 cars per hour on sundays , and 9 cars per hour on all other days of the week . if the station is open from 6 a . m . to 10 p . m . every day , how many cars does gary ’ s station serve over the course of a typical week ? 
Options: a ) 1,120 , b ) 1,200 , c ) 1,240 , d ) 1,280 , e ) 1,320
[EX A]:
a