A tourist can bicycle 28 miles in the same time as he can walk 8 miles. If he can ride 10 mph faster than he can walk, how much time (in hr) should he allow to walk a 25-mile trail? (Hint: How fast can he walk?) ________ hr. (enter a fraction)

Respuesta :

Answer:

The answer is [tex]\frac{25}{4}[/tex]

Step-by-step explanation:

Velocity formula:

[tex]v = \frac{d}{t}[/tex]

In which v is the velocity, d is the distance, and t is the time.

A tourist can bicycle 28 miles in the same time as he can walk 8 miles. He can ride 10 mph faster than he can walk:

This means that:

[tex]v = \frac{8}{t}[/tex]

And

[tex]v + 10 = \frac{28}{t}[/tex]

[tex](v + 10)t = 28[/tex]

From the first equation:

[tex]vt = 8[/tex]

So

[tex]vt + 10 = 28[/tex]

[tex]8 + 10t = 28[/tex]

[tex]10t = 20[/tex]

[tex]t = \frac{20}{10}[/tex]

[tex]t = 2[/tex]

He walks 8 miles in two hours, so:

[tex]v = \frac{8}{2} = 4[/tex]

4 miles per hour.

How much time (in hr) should he allow to walk a 25-mile trail?

This is t when [tex]d = 25[/tex]. So

[tex]v = \frac{d}{t}[/tex]

[tex]4 = \frac{25}{t}[/tex]

[tex]4t = 25[/tex]

[tex]t = \frac{25}{4}[/tex]

The answer is [tex]\frac{25}{4}[/tex]