Question

Give the units of measure for the rate.

(2, 20) and (4, 42); in x in seconds, y in feet

Answer 1

Rate here is defined as the distance travelled in feet per unit time(1 second).
The positions are: at 20 feet at time=2 second and at 42 feet at time=4second

$Rate = \frac{change\ in\ position}{change\ in\ time} = \frac{42-20}{4-2} = \boxed {\frac{22}{2}\ ft/s }$