PSLE Neave had pink pencils and black pencils for sale. He sold 360 pink pencils. 70% of the pencils sold were black.
- How many pink pencils and black pencils did Neave sell altogether?
- He sold 50% of his pencils. 60% of the pencils left unsold were pink. How many black pencils did Neave have at first?
| |
Pink |
Black |
Total |
Total in percent |
| Before |
9 u |
11 u |
20 u |
100% |
| Change |
- 30%
- 3 u |
- 70%
- 7 u |
- 100%
- 10 u |
- 50% |
| After |
60%
6 u |
40%
4 u |
100%
10 u |
50%
|
70% =
70100 =
710 Total number of pencils sold = 10 u
Number of black pencils sold = 7 u
Number of pink pencils sold
= 10 u - 7 u
= 3 u
3 u = 360
1 u = 360 ÷ 3 = 120
Total number of pencils sold
= 10 u
= 10 x 120
= 1200
(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 pink = 60%
Percent of the pencils left unsold that were black = 100% - 60% = 40%
Number of the pencils left unsold that were black
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of black pencils that Neave had at first
= 4 u + 7 u
= 11 u
= 11 x 120
= 1320
Answer(s): (a) 1200; (b) 1320
