September Mock Exam 'Korean, English, Math' Easier Than June... "Easiest After Excluding Killer Questions" (Summary)

Easier Than Last Year's 'Bulsuneung'
EBS: "Lowered Perceived Difficulty for Examinees"
Admissions Industry: "Both June and September Mock Exams' Difficulty Must Be Considered"

The Korean, Math, and English sections of the September mock exam held nationwide on the 4th were analyzed to have been easier than last year's 'bul-suneung' (extremely difficult CSAT) and this year's June mock exam.

EBS (Korea Educational Broadcasting System) gave an overall evaluation of the 2025 College Scholastic Ability Test (CSAT) September mock exam held that day, stating, "It was easier than last year's CSAT and this year's June mock exam," and added, "We focused on securing discrimination through appropriate difficulty levels."

They continued, "Although the detailed question-setting policies vary slightly by section, the broad framework of excluding so-called 'killer questions' and ensuring fairness has been maintained, and the overall question-setting policy appears unchanged," adding, "In particular, questions with high discrimination power were set as linked questions, which likely lowered the perceived difficulty."

Korean: "Easiest since exclusion of killer questions"

On the 4th, examinees were preparing for the 'September Mock Test for the 2025 College Scholastic Ability Test' held at Yeouido Girls' High School in Yeongdeungpo-gu, Seoul. Photo by Jinhyung Kang aymsdream@

Regarding the first session Korean section held that morning, EBS explained, "The information in the passages was presented relatively explicitly, and the questions were designed so that the options and passage information clearly stood out, which seems to have been arranged to alleviate time pressure."

By question, questions 11 and 16 in the reading section were analyzed as challenging. EBS explained, "Question 11 required students to clearly understand various characteristics of blockchain technology presented in the passage, then grasp the relationships among them, and accurately apply them to specific examples in the options to derive the answer, which could have been perceived as difficult by students." They added, "Question 16 required understanding the 'Bazin perspective' and 'psychoanalytic perspective' on the films presented in passages A and B, and analyzing a student's film review based on this, which could also have been difficult for test-takers."

In the speech and writing section, question 40 was identified as a high-difficulty question. EBS stated, "Question 40, which asked about the appropriateness of content reflected in the student’s impression essay in passage B considering the student's conversation in passage A and the participation review presented in the question, was likely burdensome for examinees."

Additionally, question 35 in the language and media section was analyzed as challenging. EBS explained, "To analyze the example sentence, one must be able to analyze both the sentence structure and parts of speech simultaneously," adding, "Since this is a core concept covered in school grammar, students who have thoroughly studied this should be able to solve it."

The admissions industry also evaluated the Korean section of the September mock exam as easy. Jongro Academy stated, "It was the easiest since the policy to exclude killer questions was applied," and added, "It is expected to be difficult to secure discrimination among top-tier students." They also assessed that aside from question 16, there were no difficult questions.

Megastudy also said, "It was somewhat easier compared to last year's CSAT and the June mock exam," and "It is expected that students in the field could take the exam without significant difficulty." They identified challenging questions as numbers 9 and 11 in reading, 25 in literature, 40 in speech and writing, and 35-36 in language and media.

However, there are also forecasts that the difficulty of the CSAT cannot be predicted. Daesung Academy said, "In the 2022 academic year, the top grade cutoff was 82 points in language and media in the June mock exam, but the September mock exam cutoff was 96 points, and the CSAT was also predicted to be easy," adding, "However, the actual CSAT cutoff was 81 points, and the perfect score standard score was 149 points, making it an unprecedentedly difficult CSAT." Accordingly, they advised that preparation for the 2025 CSAT should consider the difficulty levels of both the June and September mock exams. Daesung Academy analyzed that question 35 likely took some time to solve.

Math: "Moderate... 'Geometry Question 30' likely difficult"

EBS analyzed the math section as "easier than last year's CSAT and this year's June mock exam," explaining, "Questions involving content not covered in the public school curriculum, excessive calculations, or unnecessary concepts that could cause mistakes were excluded." The EBS linkage rate for the math section in this mock exam was 50% (15 out of 30 questions).

EBS added, "The difficulty of the common subjects Math I and Math II decreased, and overall calculation volume was somewhat reduced, so students likely felt it was easier than the June mock exam."

The admissions industry also viewed the difficulty of this exam as generally easy. Jongro Academy said, "It is estimated to be the easiest since the exclusion of killer questions," and added, "Both the common subjects from questions 1 to 22 and the elective subjects from questions 23 to 30 were easier compared to the June mock exam."

Questions with high discrimination power identified by both EBS and the admissions industry included question 22 (Math I), question 21 (Math II), and question 30 in Probability and Statistics, Calculus, and Geometry. Question 22 required listing terms of a sequence according to a given rule and finding the first term satisfying a condition, requiring precise understanding of the inductive definition of sequences. Question 21 required identifying the idea implied in the given conditions to find a cubic function and calculate its derivative.

Megastudy explained question 30 in Geometry as "a problem to find the maximum and minimum magnitudes of a vector created by decomposing and recombining vectors. Although once the direction is identified, the answer can be reached simply, the initial approach was likely not easy," and judged it as the highest difficulty question in Geometry.

Etus Edu commented on question 30 in Probability and Statistics, "It is expected that there was difficulty in classifying cases according to the conditions."

English: "Low discrimination among top-tier students"

On the 4th, examinees were preparing for the 'September Mock Test for the 2025 College Scholastic Ability Test' held at Yeouido Girls' High School in Yeongdeungpo-gu, Seoul. Photo by Jinhyung Kang aymsdream@

EBS analyzed the English section as "appearing easier than last year's CSAT and this year's June mock exam."

EBS stated, "Passages that were excessively abstract and difficult to understand even when translated into Korean were excluded, and questions requiring careful reading and precise understanding of the passages were set in various types to secure overall discrimination." The EBS question linkage rate was identified as 53.3%.

By question, blank inference questions 31 and 34 were considered challenging. Also, question 36 on text order and question 39 on sentence insertion were analyzed as somewhat difficult.

The admissions industry also analyzed the difficulty of this exam as moderate. Jongro Academy said, "It was much easier than last year's main CSAT," and added, "It is practically difficult to expect English discrimination among top-tier and upper-tier students."

Daesung Academy said, "Compared to the 2024 CSAT and the 2025 June mock exam, the passage topics were not difficult, and the attractiveness of incorrect options was low, so it is analyzed as having a moderate difficulty level," adding, "The blank inference and indirect writing types that were difficult in the June mock exam were also set relatively easily, so the perceived difficulty for students likely decreased." Daesung Academy identified blank inference question 34 and sentence insertion question 39 as high-difficulty questions.

Megastudy said, "Last year's CSAT had difficult order and sentence insertion questions, but this September mock exam clearly presented clues, so it likely was not difficult to solve the problems."