PSLE Vincent had yellow pencils and pink pencils for sale. He sold 630 yellow pencils. 30% of the pencils sold were pink.
- How many yellow pencils and pink pencils did Vincent sell altogether?
- He sold 50% of his pencils. 60% of the pencils left unsold were yellow. How many pink pencils did Vincent have at first?
| |
Yellow |
Pink |
Total |
Total in percent |
| Before |
13 u |
7 u |
20 u |
100% |
| Change |
- 70%
- 7 u |
- 30%
- 3 u |
- 100%
- 10 u |
- 50% |
| After |
60%
6 u |
40%
4 u |
100%
10 u |
50%
|
30% =
30100 =
310 Total number of pencils sold = 10 u
Number of pink pencils sold = 3 u
Number of yellow pencils sold
= 10 u - 3 u
= 7 u
7 u = 630
1 u = 630 ÷ 7 = 90
Total number of pencils sold
= 10 u
= 10 x 90
= 900
(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 yellow = 60%
Percent of the pencils left unsold that were pink = 100% - 60% = 40%
Number of the pencils left unsold that were pink
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of pink pencils that Vincent had at first
= 4 u + 3 u
= 7 u
= 7 x 90
= 630
Answer(s): (a) 900; (b) 630
