A, B, K start from the same place and travel in the same direction at speeds of 30km/hr, 40km/hr, 60km/hr respectively. B starts four hours after A. If B and K overtake A at the same instant, how many hours after A did K start?  Choices
A) 3	B) 4.5	C) 8	D) d) 5.5	E) e) 5
The table you made doesn't make sense to me. All three meet at the same point means the distance they cover is the same.   We know their rates are 30, 40 and 60.   Say the time taken by B is T hrs. Then A takes 4+T hrs. And we need to find the time taken by K.   Distance covered by A = Distance covered by B   30*(4+T) = 40*T   T = 12 hrs   Distance covered by B = Distance covered by K   40*T = 60*Time taken by K   Time taken by K = 40*12/60= 
<gadget id="calculator">40*12/60</gadget>
<output>8</output>
8 hrs   Time taken by A= 4+T = 4+12= 
<gadget id="calculator">4+12</gadget>
<output>16</output>
16 hrs   Time taken by K= 8 hrs   So K starts  16-8= 
<gadget id="calculator"> 16-8</gadget>
<output>8</output>
8 hrs after A. (answer 8)
<result>C</result>
A, B, K start from the same place and travel in the same direction at speeds of 30km/hr, 40km/hr, 60km/hr respectively. B starts four hours after A. If B and K overtake A at the same instant, how many hours after A did K start?