PSLE Sean had gold files and yellow files for sale. He sold 210 gold files. 40% of the files sold were yellow.
- How many gold files and yellow files did Sean sell altogether?
- He sold 50% of his files. 80% of the files left unsold were gold. How many yellow files did Sean have at first?
| |
Gold |
Yellow |
Total |
Total in percent |
| Before |
7 u |
3 u |
10 u |
100% |
| Change |
- 60%
- 3 u |
- 40%
- 2 u |
- 100%
- 5 u |
- 50% |
| After |
80%
4 u |
20%
1 u |
100%
5 u |
50%
|
40% =
40100 =
25 Total number of files sold = 5 u
Number of yellow files sold = 2 u
Number of gold files sold
= 5 u - 2 u
= 3 u
3 u = 210
1 u = 210 ÷ 3 = 70
Total number of files sold
= 5 u
= 5 x 70
= 350
(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 gold = 80%
Percent of the files left unsold that were yellow = 100% - 80% = 20%
Number of the files left unsold that were yellow
= 20% x 5 u
=
20100 x 5 u
= 1 u
Number of yellow files that Sean had at first
= 1 u + 2 u
= 3 u
= 3 x 70
= 210
Answer(s): (a) 350; (b) 210
