To find: The average rate of change of temperature of soup over the first 20 minutes and over the next 20 minutes also during which interval the soup cool off more quickly.
Therefore, the average rate of change of temperature of bowl of soup over the first 20 minutes is
Given:
The given table is,



 
0  200  35  94  
5  172  40  89  
10  150  50  81  
15  133  60  77  
20  119  920  72  
25  108  120  70  
30  100  150  70 
Formula used:
Average rate of change of function
Calculation:
The table shows the temperature (in
Temperature of bowl at time 0 min is 200
Substitute 200 for
The average rate of change of temperature of bowl of soup over the first 20 minutes is
Substitute 119 for
The average rate of change of temperature of bowl of soup over the next 20 minutes is
Where,
Form a table to show the decrease in temperature during each interval of time in the given table.





 
05  28  5.6  3540  5  0.5  
510  22  4.4  4050  8  0.8  
1015  17  3.4  5060  6  0.6  
1520  14  2.8  6090  5  0.166  
2025  11  2.2  90120  2  0.066  
2530  8  1.6  120150  0  0  
3035  6  1.2 
From the table it is clear that during first interval the soup cool off more quickly.
Therefore, the average rate of change of temperature of bowl of soup over the first 20 minutes is