Answer:
average rate of return = 13 % 
Step-by-step explanation:
given data 
equipment cost = $125,000 
residual value = $15,000
time = 8 year 
Annual Average wage = $28000
Annual operating and energy costs = $5,150
to find out 
average rate of return
solution
first we get here depreciation expenses that is here as
Depreciation expense = ( equipment cost - residual value ) ÷ time period .........1 
Depreciation expense = 

Depreciation expense = $13750 
so average annual income will be here as 
average annual income = Annual Average wage - Depreciation expense - Annual operating and energy costs ....................2
average annual income = $28,000 - $13750 -$5150
average annual income = $9100 
and average investment will be 
average investment = 

average investment = $70000 
so average rate of return will be here as
average rate of return = 
 ..............3
 ..............3
average rate of return = 
 
 
average rate of return = 0.13 
average rate of return = 13 %