Cost Volume Profit

the answer is D 11000 and i cant seem to get it even after multiple attempt

here's another question An organisation manufactures a single product which has a variable cost of $36 per unit. The organisation's total weekly fixed costs are $81,000 and it has a contribution to sales ratio of 40%. This week it plans to manufacture and sell 5,000 units. What is the organisation's margin of safety this week in units? A 1,625 B 2,750 C 3,375 D 3,500 the answer is B 2750 but I got A 1625 instead from deducting 3375 (the BEP) from the sell of 5000 units

In answer to your question If VC is 22 and CS ratio is 0.45 or 45% then cont is 45% of sales so VC must be 55% of sales That is 22 = 0.55 thus 22/0.55 = 40 so sales = 40 and cont = 45% of sales = 18 FC/CPU = BE units 198,000 / 18 = 11,000

I think the second question is incorrect