I Have Approached In Follwing Way

A and B run in opposite directions from a pt. P on a circle with different but constant speeds. A runs in clockwise direction. They meet for the first time at a distance of 900 m in clockwise direction from P and for the second time at a distance of 800 m in anticlockwise direction from P. If B is yet to complete one round, the circumference of the circle is

I TOUGHT TOTAL CIRCUMFERENCE OF CIRCLE IS X

1 ST A -> 900

B -> X-900

2ND A-> X-800

B-> 800

THEN WHAT TO DO HEAR IS MY DOUBT

PLZ SAY ANS IN BRIEF