In a class of 30 student, 2 student did not borrowed any

Question

In a class of 30 student, 2 student did not borrowed any books from the library. 12 student each borrowed 1 book, 10 students each borrowed 2 books and the rest of the students each borrowed at least 3 books. If the average (mean) number of books borrowed per students was 2. What is the maximum number of books that any student could have borrowed?

A)3
B)5
C)8
D)13
E)15

The OA is: 13

A)3
B)5
C)8
D)13
E)15

OA below

The OA is: 13

Maple · Answer

average*number of students=total number of books
2*30=60 books
30 students-12 students-10 students-2 students="rest of the students"=6 students-1 student who will borrow the maximum remaining books
set "rest of students" book borrowing to 3 books(the min) to get the max for one student
60-12*1-10*2-5*3-2*0=13 books

D

GMAT_700 · Answer

I still do not understand why do we need: 5 * 3 ?

bkk145 · Answer

# of Student, book borrowed per student
2, 0
12, 1
10, 2
6, >= 3

Set x = Total number of books borrowed by the last 6 students
Average book per student = (0+12+20+x)/30 = 2
x = 28
This means out of 6 students, 28 books were borrowed.
If 5 students borrowed minimum of 3, the last student will borrow the most number of books.
5*3 = 15
28 - 15 = 13

In a class of 30 student, 2 student did not borrowed any

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