The figures are invented. A diagram shows the market for adult training courses, with costs and benefits ($ per place) on the vertical axis and quantity (places per year) on the horizontal axis. The market output is 300 places at a price of $14. The socially optimal output is 400 places. At an output of 300 places marginal social benefit is $22 and marginal social cost is $14. Calculate the welfare loss at the market output. [2]

HL Paper 3-style calculation (standalone practice; not an IB question).