X + y = 23000
x.08 + y.09 = 2040
x = 23000 - y
(23000 - y) .08 + y.09 = 2040
1840 - .08y + .09y = 2040
Simplify
.01y = 200
Simplify
Y = 20000
X + 20000 = 23000
X = 3000
CHECK: .08x + .09(20000) = 2040
.08x + 1800 = 2040
Simply .08x = 240
X = 3000
Answer:
The solution is given in the pictures below
Step-by-step explanation:
ANSWER
Average Rate of Change

EXPLANATION
To find the average rate of change of y=f(x) from x=a to x=b means finding the slope of the secant line joining the points
(a,f(a)) and (b,f(b))
The slope of the secant line joining these points is

This gives the average rate of change of the function.