In the class of 50 students, I did a test of mathematics with four questions in total.
The students who gave the right answers of each question were 42 persons, 30 persons, 45 persons, and 37 persons, respectively.
Find a range of the number of students who got a perfect score.
The students who gave the right answers of each question were 42 persons, 30 persons, 45 persons, and 37 persons, respectively.
Find a range of the number of students who got a perfect score.
Answer
In the case of the least number of students, it is the case where there is no person who missed two or more problems which is the case where the number of student who missed only one question is the most numerous.
The numbers mistaken on each problem are 50 - 42 = 8, 50 - 30 = 20, 50 - 45 = 5 and 50 - 37 = 13.
The number is 50 - (8 + 20 + 5 + 13) = 4 students.
The range is 4 or more students and 30 students or less.
4 or more and 30 or less (More than 3 and less than 31)
Solution
In the case of the most number of students who got perfect score, it is 30 students in the case where 30 persons answer other problems correctly.
In the case of the least number of students, it is the case where there is no person who missed two or more problems which is the case where the number of student who missed only one question is the most numerous.
The numbers mistaken on each problem are 50 - 42 = 8, 50 - 30 = 20, 50 - 45 = 5 and 50 - 37 = 13.
The number is 50 - (8 + 20 + 5 + 13) = 4 students.
The range is 4 or more students and 30 students or less.
