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: working alone , pump a can empty a pool in 6 hours . working alone , pump b can empty the same pool in 9 hours . working together , how many minutes will it take pump a and pump b to empty the pool ? 
Options: a ) 192 , b ) 200 , c ) 208 , d ) 216 , e ) 224
[EX A]: d

[EX Q]: Problem: the reciprocal of the hcf and lcm of two are 1 / 13 and 1 / 312 . if one of the number is 24 then other no . is 
Options: a ) 126 , b ) 136 , c ) 146 , d ) 156 , e ) 169
[EX A]: e

[EX Q]: Problem: a goods train runs at the speed of 72 km / hr and crosses a 250 m long platform in 30 sec . what is the length of the goods train ? 
Options: a ) 299 , b ) 277 , c ) 350 , d ) 270 , e ) 281
[EX A]:
c