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'.

Q: Problem: a , b and c can complete a piece of work in 24 , 6 and 12 days respectively . working together , they will complete the same work in : 
Options: a ) 33 / 7 , b ) 43 / 7 , c ) 24 / 7 , d ) 19 / 7 , e ) none

A: c
****
Q: Problem: two trains of equal length , running with the speeds of 60 and 40 kmph , take 55 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 ) 10 sec , b ) 16 sec , c ) 13 sec , d ) 67 sec , e ) 11 sec

A: e
****
Q: Problem: in an examination , a student scores 3 marks for every correct answer and loses 1 mark for every wrong answer . if he attempts all 30 questions and secures 130 marks , the no of questions he attempts correctly is : 
Options: a ) a ) 35 , b ) b ) 40 , c ) c ) 90 , d ) d ) 88 , e ) e ) 37

A:
b
****