In order to determine who is faster it is necessary to calculate the rate of change for both table and graph.
Use the following formula for the rate of change:
m = (d2 - d1)/(h2 - h1)
where (h1,d1) and (h2,d2) are two points on the line or any pair of values on the table.
John:
use (d1,h1) = (0,0) and (d2,h2) = (1,4):
m = (4-0)/(1-0) = 4
Sara:
use (h1,d1) = (0,0) and (h2,d2) = (1,5)
m = (5 - 0)/(1-0) = 5
You can notice that the rate of change of Sara is greater then the rate of change of John.
Hence, you can conclude that Sara is faster than John
