explanation please and thank you

Kansas Enterprises purchased equipment for $79,500 on January 1,2018 . The equipment is expected to have a ten-year life, with a residual value of $8,850 at the end of ten years. Using the double-declining balance method, the book value at December 31 , 2019 would be (Do not round your Intermediate calculations): Mutiple Choles $7,950 361,360. $58,960 $50,880