PSLE Charlie had pink notebooks and green notebooks for sale. He sold 210 pink notebooks. 70% of the notebooks sold were green.
- How many pink notebooks and green notebooks did Charlie sell altogether?
- He sold 50% of his notebooks. 75% of the notebooks left unsold were pink. How many green notebooks did Charlie have at first?
|
Pink |
Green |
Total |
Total in percent |
Before |
10.5 u |
9.5 u |
20 u |
100% |
Change |
- 30% - 3 u |
- 70% - 7 u |
- 100% - 10 u |
- 50% |
After |
75% 7.5 u |
25% 2.5 u |
100% 10 u |
50%
|
70% =
70100 =
710 Total number of notebooks sold = 10 u
Number of green notebooks sold = 7 u
Number of pink notebooks sold
= 10 u - 7 u
= 3 u
3 u = 210
1 u = 210 ÷ 3 = 70
Total number of notebooks sold
= 10 u
= 10 x 70
= 700
(b)
Percent of the notebooks left unsold = 100% - 50% = 50% 50% of the notebooks that were sold = 10 u 50% of the notebooks that were left unsold = 10 u Percent of the notebooks left unsold that were pink = 75%
Percent of the notebooks left unsold that were green = 100% - 75% = 25%
Number of the notebooks left unsold that were green
= 25% x 10 u
=
25100 x 10 u
= 2.5 u
Number of green notebooks that Charlie had at first
= 2.5 u + 7 u
= 9.5 u
= 9.5 x 70
= 665
Answer(s): (a) 700; (b) 665