A start walking from a place at a uniform speed of 4 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.  Choices:
A) 4.7 kmph
B) 4.6 kmph
C) 4 kmph
D) 7 kmph
E) 5.3 kmph
Distance covered by A in 30 min = 1 Km   B covers extra 1km in 1 hour 48 minutes (9/5 hr)   i.e. Relative speed of 4.6 kmph over A = 1/(9/5) = 5/9   So the speed of 4.6 kmph = Speed of A + 5/9   = 4 + 5/9   = 4.55   Answer 4.6 kmph
<result>B</result>
A start walking from a place at a uniform speed of 4 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.