Final answer:
The average investment per month in the business during the year was $8,500.
Step-by-step explanation:
The average investment per month in the business during the year can be calculated by adding up the total investment and dividing it by the number of months:
Total Investment = $90,000 + $10,000 + $2,000 = $102,000
Total Months = 12
Average Investment per Month = Total Investment / Total Months = $102,000 / 12 = $8,500