Respuesta :

40 mi / h = 120 mi / 3h

Answer:

As per the statement:

Sarah drove 40 miles per hour in 3 hours,  Sarah drove 120 miles.

Since, speed(s) is proportional to time(t)

Using Inverse proportional.

[tex]s \propto \frac{1}{t}[/tex]

⇒[tex]s = \frac{d}{t}[/tex], where, d is the constant distance

We can write this as:

[tex]st = d[/tex]

or

[tex]d = st[/tex]

Check:

Sarah drove 40 miles per hour in 3 hours

⇒s = 40 miles per hour and t = 3 hours

then;

[tex]d= 40 \cdot 3 = 120 miles[/tex]

⇒Sarah drove 120 miles.

therefore, a valid proportion to represent the problem is, [tex]d = st[/tex]