[填空题]
A race car driver must average 200.0 km/h over the course+ r0y +tm rdvrpgx21d67x /ied9x;dnl of a time trial last,r 5j czkj.il94 nvgmz*68 mgting ten laps. If the first nine laps were done at 198.0 ktzir ,v5k*6 nl9 .jg8 gmc4mjzm/h . what average speed must be maintained for the last lap? km/h