A and B walk around a circular track. They start at 8 a.m. from the same point in the opposite directions. A and B walk at a speed of 3 rounds per hour and 3 rounds per hour respectively. How many times shall they cross each other before 9.30 a.m. ?  Choose the correct answer
A) A)5	B) B)6	C) C)8	D) D)9	E) E)87
Relative speed = 3 + 3= 
<gadget id="calculator">3 + 3</gadget>
<output>6</output>
6 rounds per hour.   So, they cross each other 6 times in an hour and 3 times in half an hour.   Hence, they cross each other 9 times before 9.30 a.m.   ANSWER:9
<result>D</result>
A and B walk around a circular track. They start at 8 a.m. from the same point in the opposite directions. A and B walk at a speed of 3 rounds per hour and 3 rounds per hour respectively. How many times shall they cross each other before 9.30 a.m. ?