since you want to find the unit rate you must take the 5 square feet to make it 1. Therefore you must divide the 5,but what you do to 1 side you have to do to another so you also have to divide 80 by 5 giving you a ratio of 16:1. Showing that there are 16 carrots per square foot.
I would choose to use the equation with feet per hour. Submarines reach such great depths that I feel this unit of measurements better represents the magnitude of those depths.
