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: some persons can do a piece of work in 12 days . two times the number of these people will do half of that work in ?
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 8
a

Problem: two trains t 1 and t 2 start simultaneously from two stations x and y respectively towards each other . if they are 70 km apart both 3 and 6 hours after start , then find the distance between the two stations .
Options: a ) 210 km , b ) 240 km , c ) 220 km , d ) 180 km , e ) 190 km
a

Problem: a cistern can be filled by a tap in 2 hours while it can be emptied by another tap in 4 hours . if both the taps are opened simultaneously then after how much time will the cistern get filled ?
Options: a ) 2 hr , b ) 5 hr , c ) 7 hr , d ) 1 hr , e ) 4 hr
e