平成24年度 春期 ITパスポート試験 問89

※ Our check while writing this explanation could not fully confirm the published answer; scoring follows IPA's official key.

• ×Incorrectア

  «0, 10, 10, 0». The values in columns 2, 3 and 4 are correct, but making column 1 zero is wrong. In column 1 both «Is a member» and «Has charges for multiple courses in the same month» are Y, that is, it is the combination that satisfies both applicable conditions, so by ③ of item (5) of the preamble the discount rate must be 20. Since satisfying only one of the conditions already gives a 10% discount under ① or ②, it is impossible for the discount to become 0 when both are satisfied.

• ×Incorrectイ

  «0, 10, 10, 20». Column 1 is given as 0 and column 4 as 20, so the correspondence between the truth values of the conditions and the discount rates is swapped end to end. Column 4 has «Is a member» = N and «Has charges for multiple courses in the same month» = N, a combination that matches none of the applicable conditions ①②③, so its discount rate must be 0. Conversely, column 1, where both are Y, falls under ③ and is 20. As a sequence of values it does contain the four correct numbers, but they are matched to the wrong columns.

• ×Incorrectウ

  «10, 10, 10, 0». The 0 in column 4 is correct, but making column 1 equal to 10 is wrong. Rule ③ of item (5) of the preamble states that when both ① and ② apply, each course gets 20% off its tuition fee; that is, it fixes the discount rate for the overlapping case separately from the single-condition cases. Column 1, where both are Y, must therefore be set to 20, distinguished from column 2 (only ① applies) and column 3 (only ② applies), which are both 10. If every matching column were set uniformly to 10, there would be no point in having rule ③ at all, and as test data it would be impossible to verify the ③ branch.

• ○エ

  正解 The correct answer is エ, «20, 10, 10, 0». Table 2 is a decision table: the top two rows are the conditions that the test must distinguish, and the third row gives the result for that column (the discount rate of the tuition fee). Since 'a' is a single cell merged across all four columns, what you have to answer is the four discount rates listed in order starting from the left-hand column. The discount scheme in item (5) of the preamble to question set B has three rules: ① an applicant who is a member gets 10% off the tuition fee; ② when the same applicant is charged for several courses that start in the same month, each course gets 10% off its tuition fee; ③ when both ① and ② apply, each course gets 20% off its tuition fee. Applying these to each column of Table 2: column 1 has «Is a member» = Y and «Has charges for multiple courses in the same month» = Y, so ③ applies and the rate is 20. Column 2 is Y and N, so only ① applies and the rate is 10. Column 3 is N and Y, so only ② applies and the rate is 10. Column 4 is N and N, so none of ①②③ applies, there is no discount, and the rate is 0. Read from the left, the values are therefore 20, 10, 10, 0, so エ is appropriate. Note also that the discount applies only to the tuition fee; the textbook fee is out of scope, as item (5) of the preamble states explicitly that no discount applies to the textbook fee. In Q90 of the same question set, when Oyo Jiro, a non-member (general) applicant, takes both Course Q and Course R starting in September, the tuition fee of Course R becomes 18,000 yen instead of 20,000 yen (the 10% discount of ②), which also confirms that column 3 is 10.