PSLE Sean had blue files and gold files for sale. He sold 270 blue files. 40% of the files sold were gold.
- How many blue files and gold files did Sean sell altogether?
- He sold 50% of his files. 60% of the files left unsold were blue. How many gold files did Sean have at first?
| |
Blue |
Gold |
Total |
Total in percent |
| Before |
6 u |
4 u |
10 u |
100% |
| Change |
- 60%
- 3 u |
- 40%
- 2 u |
- 100%
- 5 u |
- 50% |
| After |
60%
3 u |
40%
2 u |
100%
5 u |
50%
|
40% =
40100 =
25 Total number of files sold = 5 u
Number of gold files sold = 2 u
Number of blue files sold
= 5 u - 2 u
= 3 u
3 u = 270
1 u = 270 ÷ 3 = 90
Total number of files sold
= 5 u
= 5 x 90
= 450
(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 blue = 60%
Percent of the files left unsold that were gold = 100% - 60% = 40%
Number of the files left unsold that were gold
= 40% x 5 u
=
40100 x 5 u
= 2 u
Number of gold files that Sean had at first
= 2 u + 2 u
= 4 u
= 4 x 90
= 360
Answer(s): (a) 450; (b) 360
