The figure above shows the marginal social cost curve of generating electricity and the marginal private cost curve. The marginal cost paid by the producers and everyone else in society when 200 billion kilowatt hours are produced is

A bond is selling for $1000 and it pays $150 in interest a year. If the interest rate changes to 20 percent, then

A) the price of the bond falls to $750. B) the interest payment falls to $75. C) the interest payment rises to $200. D) the price of the bond rises to $1500.

Winnie's Car Wash is a perfectly competitive firm. The table above shows Winnie's total product schedule. If the price of a car wash is $4, and Winnie maximizes his profit when he employs 4 workers, the wage rate is

A) $90 per day. B) $30 per day. C) $70 per day. D) $50 per day.