A boy spots a balloon moving with the wind in a horizontal line at a height of 88.2 m from the ground level. The distance of his eye level from the ground is 1.2 m. The angle of elevation of the balloon from his eyes at an instant is 60 degree. After some time, from the same point of observation, the angle of elevation of the balloon reduces to 30 degree. Find the distance covered by the balloon during the interval.