Two boys starts from the same place walking at the rate of
5 kmph and 5.5 kmph respectively in the same direction. What time will they take to be 8.5 km apart?  Choose the most appropriate option:
A) 17hr
B) 14 hr
C) 12 hr
D) 20 hr
E) 22 hr
relative speed = 5.5 - 5= 
<gadget id="calculator">5.5 - 5</gadget>
<output>0.5</output>
0.5 kmph   distance= 8.5 km   time = distance/speed = 8.5/0.5= 
<gadget id="calculator">8.5/0.5</gadget>
<output>17</output>
17 hr   17hrNSWER 17hr
<result>A</result>
Two boys starts from the same place walking at the rate of
5 kmph and 5.5 kmph respectively in the same direction. What time will they take to be 8.5 km apart?