Answer:
See the answers and the explanation below.
Step-by-step explanation:
To solve these questions we must understand that speed is the relationship between the displacement and the time that the displacement lasts.
1. 300 [km], in 5 [hr]
d = displacement [km]

where:
v = velocity [km/h]
t = time [hr]
![v = 300/5\\v = 60 [km/h]](https://img.qammunity.org/2021/formulas/physics/college/nb6s0ly8imjdknu3yrwrry3bysdd0by61a.png)
In one hour :
![d = 60*1\\d = 60 [km]](https://img.qammunity.org/2021/formulas/physics/college/6xkv1c5dnkvmknu87g2hcon8u543ujupzz.png)
b. Car B 100 [km] in 2 [hr]
![v =100/2\\v = 50 [km/h]\\](https://img.qammunity.org/2021/formulas/physics/college/u2c26uc8cevbgs3c9826ismxwh36pmojkd.png)
C. The car A has the greatest average speed.