两辆车同时从同一位置驶向同一方向。第一辆车的速度为50 km / h，第二辆车的速度为60 km / h。两辆车之间的距离达到20公里所需的小时数是_________。
注意：这是数值类型的问题。
(A) 1
(B) 2
(C) 3
(D) 6答案： (B)
说明：在同一时间从同一位置送出两辆汽车，并以50 km / h和60 km / h的速度向同一方向行驶。
因此，在1小时后，
distance traveled by first car (with speed of 50 km/h) = 50*1 = 50 km
And, distance traveled by second car (with speed of 60 km/h) = 60*1 = 60 km
So, distance between these cars = 60 - 50 = 10 km 2小时后，
distance traveled by first car (with speed of 50 km/h) = 50*2 = 100 km
And, distance traveled by second car (with speed of 60 km/h) = 60*2 = 120 km
So, distance between these cars = 120 - 100 = 20 km 替代方式：
→ (distance traveled by second car) - (distance traveled by first car) = 20 km
→ (S2*T) - (S1*T) = 20
→ (60*T) - (50*T) = 20
→ 10*T = 20
→ T = 2 因此，选项(B)是正确的。这个问题的测验