PSLE Charlie had green notebooks and blue notebooks for sale. He sold 60 green notebooks. 60% of the notebooks sold were blue.
- How many green notebooks and blue notebooks did Charlie sell altogether?
- He sold 50% of his notebooks. 75% of the notebooks left unsold were green. How many blue notebooks did Charlie have at first?
|
Green |
Blue |
Total |
Total in percent |
Before |
5.75 u |
4.25 u |
10 u |
100% |
Change |
- 40% - 2 u |
- 60% - 3 u |
- 100% - 5 u |
- 50% |
After |
75% 3.75 u |
25% 1.25 u |
100% 5 u |
50%
|
60% =
60100 =
35 Total number of notebooks sold = 5 u
Number of blue notebooks sold = 3 u
Number of green notebooks sold
= 5 u - 3 u
= 2 u
2 u = 60
1 u = 60 ÷ 2 = 30
Total number of notebooks sold
= 5 u
= 5 x 30
= 150
(b)
Percent of the notebooks left unsold = 100% - 50% = 50% 50% of the notebooks that were sold = 5 u 50% of the notebooks that were left unsold = 5 u Percent of the notebooks left unsold that were green = 75%
Percent of the notebooks left unsold that were blue = 100% - 75% = 25%
Number of the notebooks left unsold that were blue
= 25% x 5 u
=
25100 x 5 u
= 1.25 u
Number of blue notebooks that Charlie had at first
= 1.25 u + 3 u
= 4.25 u
= 4.25 x 30
= 127.5
Answer(s): (a) 150; (b) 127.5