8x>420
x> or =52.5
52.5 mph average speed
easy stuff kid
Answer:
[tex]v\ge52.5 mph[/tex]
Step-by-step explanation:
[tex]s=420m\\ t=8h\\ v=?\\ t\ge \frac sv \\ 8\ge \frac{420}v \ \ \ \ |\cdot v\\ 8v\ge 420\ \ \ |:8\\ v\ge \frac{420}8\ \to \ v\ge 52.5 mph[/tex]
