PSLE Flynn had pink files and black files for sale. He sold 490 pink files. 30% of the files sold were black.
- How many pink files and black files did Flynn sell altogether?
- He sold 50% of his files. 60% of the files left unsold were pink. How many black files did Flynn have at first?
| |
Pink |
Black |
Total |
Total in percent |
| Before |
13 u |
7 u |
20 u |
100% |
| Change |
- 70%
- 7 u |
- 30%
- 3 u |
- 100%
- 10 u |
- 50% |
| After |
60%
6 u |
40%
4 u |
100%
10 u |
50%
|
30% =
30100 =
310 Total number of files sold = 10 u
Number of black files sold = 3 u
Number of pink files sold
= 10 u - 3 u
= 7 u
7 u = 490
1 u = 490 ÷ 7 = 70
Total number of files sold
= 10 u
= 10 x 70
= 700
(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 pink = 60%
Percent of the files left unsold that were black = 100% - 60% = 40%
Number of the files left unsold that were black
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of black files that Flynn had at first
= 4 u + 3 u
= 7 u
= 7 x 70
= 490
Answer(s): (a) 700; (b) 490
