PSLE Ahmad had black files and orange files for sale. He sold 150 black files. 70% of the files sold were orange.
- How many black files and orange files did Ahmad sell altogether?
- He sold 50% of his files. 60% of the files left unsold were black. How many orange files did Ahmad have at first?
| |
Black |
Orange |
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 orange files sold = 7 u
Number of black files sold
= 10 u - 7 u
= 3 u
3 u = 150
1 u = 150 ÷ 3 = 50
Total number of files sold
= 10 u
= 10 x 50
= 500
(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 black = 60%
Percent of the files left unsold that were orange = 100% - 60% = 40%
Number of the files left unsold that were orange
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of orange files that Ahmad had at first
= 4 u + 7 u
= 11 u
= 11 x 50
= 550
Answer(s): (a) 500; (b) 550
