Answer:
Margo walks 1 mile
Explanation:
Given that;
Margo walks to her friend's house in 10 minutes.
Using the same route, it takes Margo 20 minutes to get back home.
Total walking rate = 20+ 10 = 30 minutes
The average of her walking rate for the entire trip is 4 miles per hour
i.e 30/2 minutes = 4 miles/hr
15 minutes = 4 miles/hr
Let x be the total number of miles that Margo walk;
So;
15 minutes × x = 4 miles/hr
15 minutes × x = 4 miles/ 60 minutes
x = (4 miles/ 60 minutes) × 15 minutes
x = 1 mile
Thus, Margo walks 1 mile