Answer:
Average operating assets is $900,000
Step-by-step explanation:
The formula for return on investment stated below is the starting for solving this question:
return on investment= Net operating income / Average operating assets
return on investment is 10%
net operating income is the same as controllable margin of $90,000
Average operating assets is the unknown
10%=90000/average operating assets
average operating assets=90000/10%
average operating assets=$900,000