PSLE Xavier had blue files and gold files for sale. He sold 90 blue files. 70% of the files sold were gold.
- How many blue files and gold files did Xavier sell altogether?
- He sold 50% of his files. 60% of the files left unsold were blue. How many gold files did Xavier have at first?
| |
Blue |
Gold |
Total |
Total in percent |
| Before |
9 u |
11 u |
20 u |
100% |
| Change |
- 30%
- 3 u |
- 70%
- 7 u |
- 100%
- 10 u |
- 50% |
| After |
60%
6 u |
40%
4 u |
100%
10 u |
50%
|
70% =
70100 =
710 Total number of files sold = 10 u
Number of gold files sold = 7 u
Number of blue files sold
= 10 u - 7 u
= 3 u
3 u = 90
1 u = 90 ÷ 3 = 30
Total number of files sold
= 10 u
= 10 x 30
= 300
(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 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 10 u
=
40100 x 10 u
= 4 u
Number of gold files that Xavier had at first
= 4 u + 7 u
= 11 u
= 11 x 30
= 330
Answer(s): (a) 300; (b) 330
