OG详解-OG7 数学1 Q40

The correct answer is 5. For the graph shown, x represents time, in minutes, and y represents temperature, in degrees Celsius (ºC). Therefore, the average rate of change, in ºC per minute, of the recorded temperature of the air in the chamber between two x-values is the difference in the corresponding y-values divided by   the difference in the x-values. The graph shows that at x = 5, the corresponding y-value is 14. The graph also shows that at x = 7, the corresponding y-value is 24. It follows that the average rate of change, in ºC per minute, from x = 5 to x = 7 is  24−147−5​ , which is equivalent to 10​2​ , or 5.