Gandolfi Construction Co. purchased a used CAT 336DL earth mover at a cost of $325,000 in January 2013. The companys estimated useful life of this heavy equipment is 10 years, and the estimated salvage value is $75,000.

Assume that Gandolfi Construction Co. calculated depreciation expense for the CAT 336DL earth mover on the straight-line method and reported $480,000 of net income for the year ended December 31, 2013. The companys average total assets for 2013 were $3,000,000.

Calculate what Gandolfis ROI would have been for the year ended December 31, 2013, had the company used the double-declining-balance depreciation method for the CAT 336DL earth mover.