Michael is an Internet service provider. On December 31, 2014, he bought an existing business with servers and a building worth $300,000. During 2015, he bought new servers for $400,000. The market value of his older servers fell by $100,000. Michael's gross investment during 2015 was $ Michael's depreciation during 2015 was $ Michael's net investment during 2015 was $ Michael's capital at the end of 2015 was $