Three persons moving on a circular pond

A, B and C are in the surroundings of a circular pond as shown in a figure at equal intervals.

They began to run at the same time in the direction of the arrow in a figure respectively with the same speed.

When two of three persons meet, the two persons run with the speed same for opposite.

Three person’s speed is 150 m/m.

Answer the following questions.

(1) It took 10 minutes for A to meet B 2nd time from the start. Find the length of a round of the pond.

(2) Find the time for three persons to return the original position at the same time from the start.

Moreover, find the sum total number of times with which two of three persons meet in the time.

Answer