Two men starting from the same place walk at the rate of 5 kmph and 5.5 kmph respectively. What time will they take to be 6.5 km apart, if they walk in the same direction?
Choices:  A) 12 hrs  B) 13 hrs  C) 15 hrs  D) 17 hrs  E) None
Sol.   to be 0.5 km apart, they take 1 hour.   To be 6.5 km apart, they take [1/0.5 * 6.5= 
<gadget id="calculator">1/0.5 * 6.5</gadget>
<output>13</output>
13 hrs.   Answer 13 hrs
<result>B</result>
Two men starting from the same place walk at the rate of 5 kmph and 5.5 kmph respectively. What time will they take to be 6.5 km apart, if they walk in the same direction?