765 / 9 = 85
9*100 = 900 but this is too much
900 - 765 = 135
9 goes into 135 15 times (9*10=90 which leaves 45 which is 9*5 so 5+10) so you minus 15 from the 100 that made 900
so 100 - 15 = 85
Answer:

Step-by-step explanation:
Here is the complete question: Find the rate of change for the situation:
A chef cooks 9 lbs of chicken for 36 people and 17 lbs of chicken for 68 people.
Given: 1st situation, A chef cook 9 lbs chicken for 36 people.
2nd situation, chef cook 17 lbs chicken for 68 people.
∴ 1st situation, weight of chicken per person= 
Weight of chicken per person= 
2nd situation, weight of chicken per person= 
Weight of chicken per person= 
In both the situation chef cook same amount of chicken per person, which is 
∴ Rate of change is 