Usually, a ratio is a comparison of two numbers as a fraction a/b, whereas a rate is a comparison of two quantities with different units. So, you can talk about the ratio 5:3, or the rate five miles per three hours.
A mountain climber is 3200 meters from the peak. He climbs 50 meters per hour for 8 hours per day. How many days will it be before he reaches the peak?
The first job is to figure out the rate per day.