Deepthi Subbu wrote:In a class of 30 students , 2 didnot borrow any books , 12 borrowed 1 book , 10 borrowed 2 books and the rest borrowed atleast 3 books . The average (arithematic mean) no of book borrowed per student was 2. What is the maximum number of books that any single student could have borrowed?
1. 3
2. 5
3. 8
4. 13
5. 15
OA is D
Total number of books borrowed = (average)*(number of students) = 2*30 = 60.
Since 2 students do not borrow any books, the number of students borrowing = 30-2 = 28.
Now we can plug in the answer choices, which represent the maximum number of books any single student could have borrowed.
Answer choice E: 1 student borrows 15 books.
60-15 = 45 books left.
10 borrowed 2 books each = 10*2 = 20 books.
45-20 = 25 books left.
12 borrowed 1 book = 12*1 = 12 books.
25-12 = 13 books left.
Number of borrowers left = 28-1-10-12= 5.
5 students left borrow at least 3 books each = 5*3 = 15 books.
Doesn't work because only 13 books are left.
Since we need 2 more books to be left for the 5 remaining students, the maximum number that a student can borrow must decrease by 2.
The correct answer is
D.
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