PSLEBooks in a class library are grouped according to the following four types: Mystery, Science, Computer, and Poetry. 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 Computer type?
- There were 36 pupils in the class. Every pupil in the class took three or four books home to read over the weekend. No book was left in the classroom. How many pupils took three books home?
(a)
Total number of books
= 22 + 25 + 50 + 28
= 125
Percentage of books that was Computer
=
50125 x 100%
=
25 x 100%
= 40%
(b)
Number of pupils who took 4 books |
Number of books taken |
Number of pupils who took 3 books |
Number of books taken |
Total number of books taken |
36 |
36 x 4 = 144 |
0 |
0 |
144 |
35 |
35 x 4 = 140 |
1 |
3 |
143 |
Difference in the number of books taken if 1 more student takes 3 books instead of 4
= 144 - 143
= 1
Total difference in the number of books taken
= 144 - 125
= 19
Number of pupils who took three books home
= 19 ÷ 1
= 19
Answer(s): (a) 40%; (b) 19