Answer:
Her usual rate is 0.8333 miles per hour.
Step-by-step explanation:
The velocity formula is given by:
[tex]v = \frac{d}{t}[/tex]
In which d is the distance and t is the time.
She completed the first half of the walk 1 mi/h faster than usual
Her usual rate is v. 1mph faster is v + 1.
The second half of the walk 2 mi/h slower than the first half.
The first half is v + 1.
2mph slower is v + 1 - 2 = v - 1. Then
Total rate:
7.2 hours, and 6 miles. So
One half is v+1 and the other is v - 1. This is why each is multiplied by 0.5.
[tex]0.5(v + 1) + 0.5(v - 1) = \frac{6}{7.2}[/tex]
[tex]0.5v + 0.5 + 0.5v - 0.5 = 0.8333[/tex]
[tex]v = 0.8333[/tex]
Her usual rate is 0.8333 miles per hour.
