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: a start walking from a place at a uniform speed of 7 kmph in a particular direction . after half an hour , b starts from the same place and walks in the same direction as a at a uniform speed and overtakes a after 1 hour 48 minutes . find the speed of b . 
Options: a ) 4.7 kmph , b ) 7.6 kmph , c ) 4 kmph , d ) 7 kmph , e ) 5.3 kmph
[EX A]: b

[EX Q]: Problem: the speed of a boat in still water is 15 km / hr and the rate of current is 3 km / hr . the distance travelled downstream in 12 minutes is 
Options: a ) 1.2 km , b ) 1.8 km , c ) 2.4 km , d ) 3.6 km , e ) 1.6 km
[EX A]: d

[EX Q]: Problem: a runs twice as fast as b and gives b a start of 42 m . how long should the racecourse be so that a and b might reach in the same time ? 
Options: a ) 75 m . , b ) 80 m . , c ) 84 m . , d ) 100 m . , e ) none of the above
[EX A]:
c