Answer:
Rate of change is basically slope
To calculate slope you do
y2-y1 / x2- x1
Now get two random points lets say to make life easier we pick
2/110
and
5/275
Now since people is X and cost with Y
We plug it in
(2,110)
(5, 275)
Now follow the formula
5-2 / 275-110
Which is
3/ 165
Simplified
1/ 55
1/55 is your answer
