PSLE Vaidev had gold pencils and green pencils for sale. He sold 420 gold pencils. 30% of the pencils sold were green.
- How many gold pencils and green pencils did Vaidev sell altogether?
- He sold 50% of his pencils. 70% of the pencils left unsold were gold. How many green pencils did Vaidev have at first?
| |
Gold |
Green |
Total |
Total in percent |
| Before |
14 u |
6 u |
20 u |
100% |
| Change |
- 70%
- 7 u |
- 30%
- 3 u |
- 100%
- 10 u |
- 50% |
| After |
70%
7 u |
30%
3 u |
100%
10 u |
50%
|
30% =
30100 =
310 Total number of pencils sold = 10 u
Number of green pencils sold = 3 u
Number of gold pencils sold
= 10 u - 3 u
= 7 u
7 u = 420
1 u = 420 ÷ 7 = 60
Total number of pencils sold
= 10 u
= 10 x 60
= 600
(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 gold = 70%
Percent of the pencils left unsold that were green = 100% - 70% = 30%
Number of the pencils left unsold that were green
= 30% x 10 u
=
30100 x 10 u
= 3 u
Number of green pencils that Vaidev had at first
= 3 u + 3 u
= 6 u
= 6 x 60
= 360
Answer(s): (a) 600; (b) 360
