eitijan wrote:Source: GMATTutor
Q) What is the median number of books purchased per student in a certain class?
(1) Exactly 35% of the students in the class purchased two or fewer books.
(2) Exactly 25% of the students in the class purchased four or more books.
The median is either the middle value of a set or, if there are an even number of values in the set, the mean of the two middle values.
Statement 1 tells us that the bottom 35% of the values of the set are ≤ 2.
That tells us nothing about what the middle value is. It could be 3, or 100, or anything greater than 2.
Insufficient.
Statement 2 tells us that the highest 25% of the values in the set are ≥ 4. That leaves 75% who bought fewer than 4 books, and within that 75% is the median number of books.
From that we know that the median value is < 4, but it could be 3, 2, 1 or 0.
Combined the statements tell us that exactly 35% bought 2 or fewer and exactly 25% bought 4 or more. since 35% + 25% = 60%, in the middle are left 40% who bought more than 2 and fewer than 4 books. The students making up the 40% must have all bought 3 books. Since somewhere in the middle 40% is the middle value, the median must be 3.
The correct answer is
C.
