The break-even chart in the figure is for a small pump-impeller line. The fixed-cost, total-cost and sales-revenue lines are straight; their values at an output of 12 000 units per year are marked on the figure. The plant plans to produce and sell 10 000 units per year. Determine (a) the break-even quantity (answer in units per year), (b) the annual profit at the planned output (answer in Tk) and (c) the margin of safety at the planned output as a percentage of planned output (answer in %).