[tex]\large \orange{\underbrace{\bf{ \red{\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: Question \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: }}}}[/tex]

A person, standing on a railway platform, noticed that a train took 21 seconds to completely cross the platform which is 84 m long and it took 9 seconds in crossing him. The speed of the train is
________________________________
[tex] \blue{ \underbrace {\bf{ \green{ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: Options \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: }}}}[/tex]

A- 25.2km/hr
B- 32.4km/hr
C- 50.4km/hr
D- 75.64km/hr
________________________________

[tex] \\ \\ \\ \\ [/tex]
​