平成30年度秋期 ITパスポート試験問16

This question's explanation and your answers so far.

問16

頻出度★★★

ある会社の昨年度の売上高は3,000万円，年度末の在庫金額は600万円，売上総利益率は20%であった。このとき，在庫回転期間は何日か。ここで，在庫回転期間は簡易的に次の式で計算し，小数第1位を四捨五入して求める。在庫回転期間＝（期末の在庫金額÷1年間の売上原価）×365

出典　平成30年度秋期 ITパスポート試験問16

解説

問 16

Incorrectア
58 days. This value can appear when several mistakes are combined — such as not correctly computing the cost of sales as 24,000,000 yen but instead reducing the inventory amount by the profit margin (600×0.8＝480), or using sales in the denominator — but it does not match the correct formula (600÷2,400)×365＝91.25, so it is wrong.
Incorrectイ
73 days. A typical mistake of not converting the denominator to the cost of sales but computing (600÷3,000)×365＝73 using sales of 30,000,000 yen as is. The formula in the question has the cost of sales as the denominator, and this skips the step of first finding the cost of 24,000,000 yen from the gross profit margin.
Incorrectウ
88 days. A confusing value that arises when the cost of sales is calculated incorrectly or the rounding is handled wrongly. Correctly, using a cost of sales of 24,000,000 yen gives (600÷2,400)×365＝91.25→91 days, not 88 days.
エ
正解 The key is that the denominator of the inventory turnover period formula is the annual cost of sales, not sales itself. First, find the cost of sales. Since the gross profit margin is 20%, the cost of sales is (1−0.2)＝80% of sales. Cost of sales ＝ 30,000,000 yen × 0.8 ＝ 24,000,000 yen. Substituting into the formula, inventory turnover period ＝ (end-of-period inventory 6,000,000 yen ÷ cost of sales 24,000,000 yen) × 365 ＝ 0.25 × 365 ＝ 91.25 days. Rounding the first decimal place gives 91 days, so the correct answer is エ.

ここがポイント

Inventory turnover period ＝ inventory value ÷ cost of sales × 365. The denominator is not sales but the cost of sales, and the key point is to first find cost of sales ＝ sales × (1−profit margin) from the gross profit margin.
The inventory turnover period is an efficiency indicator showing how many days' worth of inventory is held; the shorter it is, the more efficiently the inventory is turning over.

用語

解答問16エ