the number of crimes that occurred in a certain city per 100

the number of crimes that occurred in a certain city per 1000 people has decreased from 45.5. in 1920 to 44.7 in 1960. Find the average rate of change in the number of crimes per 1000 people that occurred from 1920 to 1960

Solution

given

crimes in 1920 =45.5 per 1000 people

crimes in 1960 =44.7 per 1000 people

average rate of change in number of crimes =[number of crimes in 1960 -number of crimes in 1920]/[1960-1920]

average rate of change in number of crimes =[44.7-45.5]/[40]

average rate of change in number of crimes =-0.02

crimes decreased by 0.02 per year per 1000 people