PSLE Carl had black markers and silver markers for sale. He sold 90 black markers. 40% of the markers sold were silver.
- How many black markers and silver markers did Carl sell altogether?
- He sold 50% of his markers. 70% of the markers left unsold were black. How many silver markers did Carl have at first?
| |
Black |
Silver |
Total |
Total in percent |
| Before |
6.5 u |
3.5 u |
10 u |
100% |
| Change |
- 60%
- 3 u |
- 40%
- 2 u |
- 100%
- 5 u |
- 50% |
| After |
70%
3.5 u |
30%
1.5 u |
100%
5 u |
50%
|
40% =
40100 =
25 Total number of markers sold = 5 u
Number of silver markers sold = 2 u
Number of black markers sold
= 5 u - 2 u
= 3 u
3 u = 90
1 u = 90 ÷ 3 = 30
Total number of markers sold
= 5 u
= 5 x 30
= 150
(b)
Percent of the markers left unsold = 100% - 50% = 50% 50% of the markers that were sold = 5 u 50% of the markers that were left unsold = 5 u Percent of the markers left unsold that were black = 70%
Percent of the markers left unsold that were silver = 100% - 70% = 30%
Number of the markers left unsold that were silver
= 30% x 5 u
=
30100 x 5 u
= 1.5 u
Number of silver markers that Carl had at first
= 1.5 u + 2 u
= 3.5 u
= 3.5 x 30
= 105
Answer(s): (a) 150; (b) 105
