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: two passenger trains start at the same hour in the day from two different stations and move towards each other at the rate of 14 kmph and 21 kmph respectively . when they meet , it is found that one train has traveled 60 km more than the other one . the distance between the two stations is ?
Options: a ) 477 , b ) 420 , c ) 279 , d ) 276 , e ) 291
[EX A]: b

[EX Q]: Problem: a 600 meter long train crosses a signal post in 15 seconds . how long will it take to cross a 3 kilometer long bridge , at the same speed ?
Options: a ) 4 min , b ) 2 min , c ) 8 min , d ) 9 min , e ) 1.5 min
[EX A]: e

[EX Q]: Problem: the sector of a circle has radius of 21 cm and central angle 270 o . find its perimeter ?
Options: a ) 145 cm , b ) 135 cm , c ) 121 cm , d ) 141 cm , e ) 151 cm
[EX A]:
d