PSLEBooks in a class library are grouped according to the following four types: Poetry, History, Computer, and Self-help. The bar graph shows the number of books of each type in the class library.
- What percentage of books in the class library was of the History type?
- There were 30 students in the class. Every student in the class took two or four books home to read over the weekend. No book was left in the classroom. How many students took two books home?
(a)
Total number of books
= 26 + 18 + 13 + 43
= 100
Percentage of books that was History
=
18100 x 100%
=
950 x 100%
= 18%
(b)
Number of students who took 4 books |
Number of books taken |
Number of students who took 2 books |
Number of books taken |
Total number of books taken |
30 |
30 x 4 = 120 |
0 |
0 |
120 |
29 |
29 x 4 = 116 |
1 |
2 |
118 |
Difference in the number of books taken if 1 more student takes 2 books instead of 4
= 120 - 118
= 2
Total difference in the number of books taken
= 120 - 100
= 20
Number of students who took two books home
= 20 ÷ 2
= 10
Answer(s): (a) 18%; (b) 10