Y and Z walk around a circular track. They start at 5 a.m from the same point in the opposite directions. Y and Z walk at a speed of 3 rounds per hour and 4 rounds per hour respectively. How many times shall they cross each other before 7 a.m  Options: A) 14 B) 15 C) 16 D) 17 E) 18
18xplanation:   Relative speed = (3+4) =9 rounds per hour   So, they cross each other 9 times in an hour hence, they cross 18 times before 7 a.m   Answer: Option 18
<result>E</result>
Y and Z walk around a circular track. They start at 5 a.m from the same point in the opposite directions. Y and Z walk at a speed of 3 rounds per hour and 4 rounds per hour respectively. How many times shall they cross each other before 7 a.m