Here's the problem. Use simple payback method

A project capitalized for $10,000.00 invested in depreciable assets will earn a uniform, annual income of $8,000 in 5 years. The salvage value is $1000. The cost for operation and maintenance totals $4,000 a year, and taxes and insurance will cost 4% of the first cost each year. If the company expects its capital to earn 15% before income taxes, is the investment worthwhile