A communications satellite travels at a constant speed of 1.8 × 104 kilometers per hour. Approximately how many seconds does it take to travel 28.8 kilometers?
0.3
0.6
1.08
3
6
速度 = 1.8×104 = 18000 公里/小时
距离 = 28.8 公里
行驶 28.8 公里所需秒数 = (28.8 / 18000) × 3600 ≈ 6(秒)