To find the percentage of the course that Debra has ridden so far, we need to divide the number of miles that Debra has ridden by the total number of miles in the course. This is modeled below:
57/60 = 0.95
Next, we should multiply this decimal value by 100 to convert it to its equivalent percentage.
0.95 * 100 = 95
Therefore, Debra has ridden 95% of the course so far.
Hope this helps!