market size and market share variance

When preparing the budget, they expected the market size to be 30,000/10% = 300,000. The actual market size was 300,000 - 5% = 285,000. Therefore their actual sales will have been 15% x 285,000 = 42,750 This is 12,750 more than their budgeted sales. On the market size of 285,000 they should have had sales of 10% x 285,000 = 28,500. Therefore the market size variance is 28,500 - 30,000 = 1,500 (adverse), costed at the standard profit per unit of $600. The market share variance is 42,750 - 28,500 = 14,250 (favourable), costed at the standard profit per unit go $600.