PSLE Sam had purple pencils and yellow pencils for sale. He sold 80 purple pencils. 60% of the pencils sold were yellow.
- How many purple pencils and yellow pencils did Sam sell altogether?
- He sold 50% of his pencils. 75% of the pencils left unsold were purple. How many yellow pencils did Sam have at first?
| |
Purple |
Yellow |
Total |
Total in percent |
| Before |
5.75 u |
4.25 u |
10 u |
100% |
| Change |
- 40%
- 2 u |
- 60%
- 3 u |
- 100%
- 5 u |
- 50% |
| After |
75%
3.75 u |
25%
1.25 u |
100%
5 u |
50%
|
60% =
60100 =
35 Total number of pencils sold = 5 u
Number of yellow pencils sold = 3 u
Number of purple pencils sold
= 5 u - 3 u
= 2 u
2 u = 80
1 u = 80 ÷ 2 = 40
Total number of pencils sold
= 5 u
= 5 x 40
= 200
(b)
Percent of the pencils left unsold = 100% - 50% = 50% 50% of the pencils that were sold = 5 u 50% of the pencils that were left unsold = 5 u Percent of the pencils left unsold that were purple = 75%
Percent of the pencils left unsold that were yellow = 100% - 75% = 25%
Number of the pencils left unsold that were yellow
= 25% x 5 u
=
25100 x 5 u
= 1.25 u
Number of yellow pencils that Sam had at first
= 1.25 u + 3 u
= 4.25 u
= 4.25 x 40
= 170
Answer(s): (a) 200; (b) 170
