Answer:
[tex]v=0.95 m/s[/tex]
Explanation:
To calculate the average velocity, we need to use the formula:
[tex]v=\frac{x_{2}-x_{1} }{t_{2}-t_{1} }[/tex]
Since the entire distance that the person walk
[tex]x_{2}=(50+40)m=90m[/tex]
and,
[tex]x_{1}=50m[/tex]
The time that the person takes to do the entire trip is
[tex]t_{2}=42s+28s=70s[/tex]
Having that we can calculate the average speed
[tex]v=\frac{(90-50)m}{(70-28)s}= 0.95m/s[/tex]