Simplify, distribute the exponent outside of the parenthesis by the terms inside of it. Remember, when a value that already has an exponent is raised to another exponent, the equivalent of these two values is multiplying the exponents together. Use this property here:
Now simplify this fraction. Keep in mind that a fraction is another way of representing the operation of division. When one wants to divide terms raised to an exponent, one must make sure that these terms have a like base. Then one will subtract the exponents from each other. Do this step with terms that have a variable base:
5 miles for every 2 hours. There are 4 groups of 2 hour blocks in 8 hours, so we multiply the 5 miles*4 2 hour blocks (5*4). That leaves us with 20 miles is 8 hours.