A, B and C start from the same place and travel in the same direction at speeds of 30, 40 and 60 km per hour respectively. B starts two hours after A. If B and C overtake A at the same instant, how many hours after A did C start?

Options
1) 3
2) 3.5
4) 4
5) 4.5

• 4) 4
  
  If B & C overtakes A at at a distance 'x' ,then
  To cover distance 'x' A takes x/30 hours and B takes x/40 hours
  As B starts 2 hours after A, so difference of these two times=(x/30) - (x/40)=2 ,x=240
  Similarly C will start after A=difference of time taken to cover 'x' by A and C=(x/30)-(x/60)
  =(240/30) - (240/60)
  =4
• 8 years agoHelpfull: Yes(3) No(0)