a chocolate manufacturer produces 400 units of a certain model each month at a cost to the manufacturer of £ 40 per unit and all of the produced units are sold each month . what is the minimum selling price per unit that will ensure that the monthly profit ( revenue from sales minus production costs ) on the sales of these units will be at least £ 40000 ? Choose the correct choice from the following answers
A) 123	B) 213	C) 440	D) 550	E) 540

Rationale: 400 ( x - 40 ) ≥ 40000 x - 40 ≥ 400 x ≥ 440 answer : option c
Answer: C