A and B walk around a circular track. A and B walk at a speed of 4 rounds per hour and 4 rounds per hour respectively. If they start at 6 a.m. from the same point in opposite directions, how many times shall they cross each other before 7.00 a.m.?
Choose one.
A) 6  B) 5  C) 4  D) 8  E) 10
Relative speed = Speed of A + Speed of B (âˆ´ they walk in opposite directions)   = 4 + 4= 
<gadget id="calculator">4 + 4</gadget>
<output>8</output>
8 rounds per hour=&gt; They cross each other 8 times in 1 hour.   Time duration from 6.00 am to 7.00 am = 1 HOUR   Hence they cross each other 8 times before 7.00 am   Answer : 8
<result>D</result>
A and B walk around a circular track. A and B walk at a speed of 4 rounds per hour and 4 rounds per hour respectively. If they start at 6 a.m. from the same point in opposite directions, how many times shall they cross each other before 7.00 a.m.?