A bus and a car set out from Shanghai to Nanjing at the same time. The average travel speed of the bus is 80 kilometers per hour, and that of the car is 100 kilometers per hour, How many hours can the car catch up with the bus?

A bus and a car set out from Shanghai to Nanjing at the same time. The average travel speed of the bus is 80 kilometers per hour, and that of the car is 100 kilometers per hour, How many hours can the car catch up with the bus?

20 + 20 + 20 = 60 = 1 hour
80×1/(100-80)=4

From city a to city B, you can go by highway or by train. It takes 3.5 hours for a car to travel 120 kilometers per hour. If you take a train instead, it is 56 times of the car per hour. How many hours can you get there?

(120 × 3.5) / (120 × 56) = 420 ／ 100 = 4.2 (hours) a: 4.2 hours

On the highway, a 5-meter-long car with a speed of 120 km / h is going to overtake a 100 km / h truck twice its length. How many seconds will it take for you to overtake?
Solve by equation

X (hours) is the overtaking completion time, 120x-100x = 0.015 x = 0.00075 (hours) is 2.7 seconds

It takes 5 / 2 hours for a car with a speed of 120 km / h from Nanjing to Shanghai. How long is the expressway from Nanjing to Shanghai?
The speed of the high-speed railway is 5 / 2 of that of the car. How long does it take from Nanjing to Shanghai by high-speed railway

120 * 5 / 2 = 300 (km) this is the distance from Nanjing to Shanghai
300 / (120 * 5 / 2) = 1 (hour)
The title is: 120 * 5 / 2 / (120 * 5 / 2) = 1 (hour)
A: it takes less than one hour to get to Shanghai by high speed rail