Cost=$20,000,000. [Part of question missing, so the solution is based on guessing what the whole question is.]
Revenue for 6 years=$60,000,000 ($10,000,000 per year)
Revenue for last 4 years=$28,000,000 ($7,000,000 per year)
Total revenue: $88,000,000.
Profit=$88M-$20M=$68M over 10 years, $6.8M average in 1 year.