Question 1040789
change in score = 92 - 78 = 14 percentage points
change in hours = 4 - 1.5 = 2.5 hours


Divide the change in score over change in hours


(change in score)/(change in hours) = 14/2.5 = 5.6


The units here are percentage points per hour. 
So the final overall answer is that the rate of change is <font color=red>5.6 percentage points per hour</font>


What does this mean? It means that for every hour studied, the score has been improved by 5.6 percentage points