If hours is represented as h, your distance is therefore 3*h (due to that for every hour, you walk 3 miles. For example, in one hour you'd walk 3 miles, in 2 hours you'd walk 3+3=3*2=6 miles,etc.). If distance is represented by d, we get 3*h=d. Since you have to figure out the distance from the equation (that's the purpose of it!), the distance is the dependent variable. In addition, since you can't have 2 separate variables in one equation, h is the independent variable due to that you have to put a number for h in to figure out the distance
