Similarity between formal and informal employment

Based on the supply and demand theory, why do medical doctors earn higher wages than child-care workers?

By 2020, automobile market analysts expect that the demand for electric autos will increase as buyers become more familiar with the technology. however, the costs of producing electric autos may increase because of higher costs for inputs (e.g., rare earth elements), or they may decrease as the manufacturers learn better assembly methods (i.e., learning by doing). what is the expected impact of these changes on the equilibrium price and quantity for electric autos?

The stock of grommet corporation, a u.s. company, is publicly traded, with no single shareholder owning more than 5 percent of its outstanding stock. grommet owns 95 percent of the outstanding stock of staple inc., also a u.s. company. staple owns 100 percent of the outstanding stock of clip corporation, a canadian company. grommet and clip each own 50 percent of the outstanding stock of fastener inc., a u.s. company. grommet and staple each own 50 percent of the outstanding stock of binder corporation, a u.s. company. which of these corporations form an affiliated group eligible to file a consolidated tax return?