Question

A and B are running along a circular course of radius 7 km in opposite diection such that when they meet they reverse their directions and when they meet A will run at the speed of B and vice versa .Initially , the speed of A is thrice the speed of B .Assume that they start from Mo and they first meet at M1, then at M2 , next at M3 and then at M4 .


Q1) what is the shortest distance between M1 and M2 ??
(1) 11 km
(2) 7sqrt(2)
(3)7 km
(4)14 km

Q2) what is the distance between M1 and M2 along the course ??
(1) 22 km
(2) 14 sqrt(2)
(3) 22 sqrt (2)
(4)14 km

Q3)which is the point that coincides with Mo??
(1) M1
(2)M2
(3)M3
(4)M4

Q4) what is the distance travelled by A when they meet at M3
(1)77 km
(2)66 km
(3)99 km
(4) 88 km

Answer 1

Given that 
Radius of Circle = 7 Km
Thus Diameter = 14 Km

Answer 1)

Since M1 is the first point they reach and M2 is the same point where they started 
thus
Shortest distance between M1 and M2 = Diameter of Circle
                                                               = 14 Km
Thus Answer is 4) 14 Km

Answer 2)
long the Course
Distance between M1 and M2 = Circumference of  Semicircle
                                               = pi r
                                                = 22/ 7 * 7  = 11 Km
Thus answer is 1) 22Km
Answer 3)

Answer is 2 ) M1

Answer 4)
Distance of A at M3 = 3 pi r
                                = 3 * 22/7 * 7
                                 = 66 Km
answer is 2) 66 Km