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: the length of the bridge , which a train 130 metres long and travelling at 108 km / hr can cross in 30 seconds , is : 
Options: a ) 200 m , b ) 225 m , c ) 245 m , d ) 170 m , e ) 240 m
d

Problem: a can do a work in 8 days . b can do the same work in 16 days . if both a & b are working together in how many days they will finish the work ? 
Options: a ) 3 days , b ) 16 / 3 days , c ) 3 / 4 days , d ) 9 / 12 days , e ) 5 / 7 days
b

Problem: ram , who is half as efficient as krish , will take 21 days to complete a task if he worked alone . if ram and krish worked together , how long will they take to complete the task ? 
Options: a ) 16 days , b ) 12 days , c ) 8 days , d ) 7 days , e ) 18 days

d