計算問題を教えて下さい。
以下の正しい計算式が理解できません。
A company enters into an agreement with a firm who will factor the company's accounts receivable. The factor agrees to buy the company's receivables, which average $100,000 per month and have an average collection period of 30 days.
The factor will advance up to 80 percent of the face value of receivables at an annual rate of 10 percent and charge a fee of 2 percent on all receivables purchased.
The controller of the company estimates that the company would save $18,000 in collection expenses over the year.
Fees and interest are not deducted in advance. Assuming a 360-day year, what is the annual cost of financing?
(私が考えた計算式）
$100,000 ×12ケ月×80%×10%+$100,000×12ケ月×2%=120,000
$120,000-$18,000=$102,000
$102,000/($100,000×12ケ月×80%)=10.6%
（正解）
$100,000 ×80%×10%+$100,000×12×2%=32,000
$32,000-$18,000=$14,000
$14,000/$80,000=17.5%
お礼
早速ありがとうございました。 非常に理解できました。 深謝いたします。