Required information [The following information applies to the questions displayed below.] Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): 0. How many units must be sold to achieve a target profit of $8,100 ? (Do not round intermediate calculations.) Required information [The following information applies to the questions displayed below.] Oslo Company prepared the following contribution format income statement based on a sales volume of 1,000 units (the relevant range of production is 500 units to 1,500 units): 11-a. What is the margin of safety in dollars? (Do not round intermediate calculations.) 11-b. What is the margin of safety percentage? (Round your final answer to the nearest whole percentage (i.e, .12 should be entered as 12).)