PSLE Reggie had pink notebooks and gold notebooks for sale. He sold 90 pink notebooks. 40% of the notebooks sold were gold.
- How many pink notebooks and gold notebooks did Reggie sell altogether?
- He sold 50% of his notebooks. 70% of the notebooks left unsold were pink. How many gold notebooks did Reggie have at first?
|
Pink |
Gold |
Total |
Total in percent |
Before |
6.5 u |
3.5 u |
10 u |
100% |
Change |
- 60% - 3 u |
- 40% - 2 u |
- 100% - 5 u |
- 50% |
After |
70% 3.5 u |
30% 1.5 u |
100% 5 u |
50%
|
40% =
40100 =
25 Total number of notebooks sold = 5 u
Number of gold notebooks sold = 2 u
Number of pink notebooks sold
= 5 u - 2 u
= 3 u
3 u = 90
1 u = 90 ÷ 3 = 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 pink = 70%
Percent of the notebooks left unsold that were gold = 100% - 70% = 30%
Number of the notebooks left unsold that were gold
= 30% x 5 u
=
30100 x 5 u
= 1.5 u
Number of gold notebooks that Reggie had at first
= 1.5 u + 2 u
= 3.5 u
= 3.5 x 30
= 105
Answer(s): (a) 150; (b) 105