PSLE Michael had green files and red files for sale. He sold 100 green files. 60% of the files sold were red.
- How many green files and red files did Michael sell altogether?
- He sold 50% of his files. 80% of the files left unsold were green. How many red files did Michael have at first?
| |
Green |
Red |
Total |
Total in percent |
| Before |
6 u |
4 u |
10 u |
100% |
| Change |
- 40%
- 2 u |
- 60%
- 3 u |
- 100%
- 5 u |
- 50% |
| After |
80%
4 u |
20%
1 u |
100%
5 u |
50%
|
60% =
60100 =
35 Total number of files sold = 5 u
Number of red files sold = 3 u
Number of green files sold
= 5 u - 3 u
= 2 u
2 u = 100
1 u = 100 ÷ 2 = 50
Total number of files sold
= 5 u
= 5 x 50
= 250
(b)
Percent of the files left unsold = 100% - 50% = 50% 50% of the files that were sold = 5 u 50% of the files that were left unsold = 5 u Percent of the files left unsold that were green = 80%
Percent of the files left unsold that were red = 100% - 80% = 20%
Number of the files left unsold that were red
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of red files that Michael had at first
= 1 u + 3 u
= 4 u
= 4 x 50
= 200
Answer(s): (a) 250; (b) 200
