the length and breadth of play ground are 36 m and 21 m respectively. flag staffs are required to be fixed on all along the boundary at a distance of 3 m part. the number of flag staffs will be-----------?

the length and breadth of play ground are 36 m and 21 m respectively. flag staffs are required to be fixed on all along the boundary at a distance of 3 m part. the number of flag staffs will be-----------?