PSLE Fred had blue markers and black markers for sale. He sold 300 blue markers. 40% of the markers sold were black.
- How many blue markers and black markers did Fred sell altogether?
- He sold 50% of his markers. 60% of the markers left unsold were blue. How many black markers did Fred have at first?
| |
Blue |
Black |
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 markers sold = 5 u
Number of black markers sold = 2 u
Number of blue markers sold
= 5 u - 2 u
= 3 u
3 u = 300
1 u = 300 ÷ 3 = 100
Total number of markers sold
= 5 u
= 5 x 100
= 500
(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 blue = 60%
Percent of the markers left unsold that were black = 100% - 60% = 40%
Number of the markers left unsold that were black
= 40% x 5 u
=
40100 x 5 u
= 2 u
Number of black markers that Fred had at first
= 2 u + 2 u
= 4 u
= 4 x 100
= 400
Answer(s): (a) 500; (b) 400
