College entrance exam authorities came under fire amid a series of claims of ambiguous questions, one of which has prompted students to prepare a class action suit.Students claimed that at least three questions in English, mathematics and geography on the College Scholastic Ability Test were confusing and ambiguous.The state-run Korea Institute for Curriculum and Evaluation is scheduled to notify students of the results of the national exam Wednesday. More than 650,700 high school seniors and graduates took the test on Nov. 7.In the mathematics A section, some students took issue with instructions on question No. 18.The question asked: When distributing eight white balls and seven orange balls between three students, what is the probability of all students getting at least one ball of each color? But the question did not specify whether it was asking about the probability of receiving a specific ball or any ball of a certain color, causing confusion among students.Experts pointed out that there was no correct answer on the multiple-choice question if each same-colored ball was identified as unique.The state institute said that such a claim was invalid because it is assumed not to identify each same-colored ball unless the question explicitly describes them as “different ones.”One question in the English section also brought up complaints as its passage and answer options were almost identical with the question from a private academy’s study materials.Some test takers were also moving to file a collective suit with regard to a question in the world geography section.Question No. 8 asked test takers to pick the right explanation about the European Union and the North American Free Trade Agreement blocs.Although the answer was that the EU’s combined production was greater than that of the NAFTA members, some argued that the EU’s current gross output is actually smaller than the North American trade bloc’s.The KICE did not accept the complaint, saying that the question was based on statistics between 2007 and 2011 as written in all the textbooks.Yet, the world map shown in the question was of 2012, adding fuel to the controversies.By Lee Hyun-jeong ( rene@heraldcorp.com