PSLE Carl had green files and red files for sale. He sold 60 green files. 70% of the files sold were red.
- How many green files and red files did Carl sell altogether?
- He sold 50% of his files. 70% of the files left unsold were green. How many red files did Carl have at first?
| |
Green |
Red |
Total |
Total in percent |
| Before |
10 u |
10 u |
20 u |
100% |
| Change |
- 30%
- 3 u |
- 70%
- 7 u |
- 100%
- 10 u |
- 50% |
| After |
70%
7 u |
30%
3 u |
100%
10 u |
50%
|
70% =
70100 =
710 Total number of files sold = 10 u
Number of red files sold = 7 u
Number of green files sold
= 10 u - 7 u
= 3 u
3 u = 60
1 u = 60 ÷ 3 = 20
Total number of files sold
= 10 u
= 10 x 20
= 200
(b)
Percent of the files left unsold = 100% - 50% = 50% 50% of the files that were sold = 10 u 50% of the files that were left unsold = 10 u Percent of the files left unsold that were green = 70%
Percent of the files left unsold that were red = 100% - 70% = 30%
Number of the files left unsold that were red
= 30% x 10 u
=
30100 x 10 u
= 3 u
Number of red files that Carl had at first
= 3 u + 7 u
= 10 u
= 10 x 20
= 200
Answer(s): (a) 200; (b) 200
