PSLE Harry had green pencils and purple pencils for sale. He sold 60 green pencils. 70% of the pencils sold were purple.
- How many green pencils and purple pencils did Harry sell altogether?
- He sold 50% of his pencils. 80% of the pencils left unsold were green. How many purple pencils did Harry have at first?
| |
Green |
Purple |
Total |
Total in percent |
| Before |
11 u |
9 u |
20 u |
100% |
| Change |
- 30%
- 3 u |
- 70%
- 7 u |
- 100%
- 10 u |
- 50% |
| After |
80%
8 u |
20%
2 u |
100%
10 u |
50%
|
70% =
70100 =
710 Total number of pencils sold = 10 u
Number of purple pencils sold = 7 u
Number of green pencils sold
= 10 u - 7 u
= 3 u
3 u = 60
1 u = 60 ÷ 3 = 20
Total number of pencils sold
= 10 u
= 10 x 20
= 200
(b)
Percent of the pencils left unsold = 100% - 50% = 50% 50% of the pencils that were sold = 10 u 50% of the pencils that were left unsold = 10 u Percent of the pencils left unsold that were green = 80%
Percent of the pencils left unsold that were purple = 100% - 80% = 20%
Number of the pencils left unsold that were purple
= 20% x 10 u
=
20100 x 10 u
= 2 u
Number of purple pencils that Harry had at first
= 2 u + 7 u
= 9 u
= 9 x 20
= 180
Answer(s): (a) 200; (b) 180
