A,B are start walking around a Circular park of radius 70m. They start at the same point, and A goes clockwise at 10m/s, while b goes anti-clockwise at 20m/s.How many times will they cross each other at the starting point if they walk for 30 minutes?
a) 20
b) 40
c) 60
d) 80
e) None of the above
a) 20
b) 40
c) 60
d) 80
e) None of the above