XYZ Corporation is considering project A, which cost of $200.00 and has 4 years useful life. The company uses straight-line depuration and the project has zero salvage value at the end of 4 years. The after tax cash flow of the project for the next 4 years are $50.00, $60.00, $70.00 and $ 80.00. The average accounting rate of return (average book rate of return) of the project is?