Solution (By Examveda Team)
$$\eqalign{
& {\text{Given , }} \cr
& {\text{Train cover 3584 kms in 2 days 8 hours}} \cr
& \left( {2\,{\text{days 8 hours = }}\frac{7}{3}{\text{ days}}} \right) \cr
& {\text{Average speed = }} {\frac{{3584}}{{ {\frac{{7}}{{3}}}}}} \cr
& {\text{ = 1536 km/day = }}\frac{{1536}}{{24}}{\text{ = 64 km/h}} \cr
& {\text{Distance covered in two days}} \cr
& {\text{ = 1440 + 1608 = 3048 km}} \cr
& {\text{Remaining distance for third day}} \cr
& {\text{ = 3584 }} - {\text{3048 = 536 km}} \cr
& {\text{Third day 536 km is covered in }} \cr
& {\text{8 hour with speed of}} \cr
& {\text{ = }}\frac{{536}}{8} = 67{\text{ km/h }} \cr
& {\text{( 3rd day total 536 km distance}} \cr
& {\text{ covered by 67 km/hr in 8 hr)}} \cr
& \therefore {\text{Difference of average speedm}} \cr
& {\text{ = 67}} - {\text{64 = 3 km/hr}} \cr} $$
3rd day 8 hours of speed- from where it came?