PSLE John had red notebooks and orange notebooks for sale. He sold 150 red notebooks. 40% of the notebooks sold were orange.
- How many red notebooks and orange notebooks did John sell altogether?
- He sold 50% of his notebooks. 75% of the notebooks left unsold were red. How many orange notebooks did John have at first?
|
Red |
Orange |
Total |
Total in percent |
Before |
6.75 u |
3.25 u |
10 u |
100% |
Change |
- 60% - 3 u |
- 40% - 2 u |
- 100% - 5 u |
- 50% |
After |
75% 3.75 u |
25% 1.25 u |
100% 5 u |
50%
|
40% =
40100 =
25 Total number of notebooks sold = 5 u
Number of orange notebooks sold = 2 u
Number of red notebooks sold
= 5 u - 2 u
= 3 u
3 u = 150
1 u = 150 ÷ 3 = 50
Total number of notebooks sold
= 5 u
= 5 x 50
= 250
(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 red = 75%
Percent of the notebooks left unsold that were orange = 100% - 75% = 25%
Number of the notebooks left unsold that were orange
= 25% x 5 u
=
25100 x 5 u
= 1.25 u
Number of orange notebooks that John had at first
= 1.25 u + 2 u
= 3.25 u
= 3.25 x 50
= 162.5
Answer(s): (a) 250; (b) 162.5