PSLE Ryan had blue pens and green pens for sale. He sold 60 blue pens. 70% of the pens sold were green.
- How many blue pens and green pens did Ryan sell altogether?
- He sold 50% of his pens. 60% of the pens left unsold were blue. How many green pens did Ryan have at first?
| |
Blue |
Green |
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 pens sold = 10 u
Number of green pens sold = 7 u
Number of blue pens sold
= 10 u - 7 u
= 3 u
3 u = 60
1 u = 60 ÷ 3 = 20
Total number of pens sold
= 10 u
= 10 x 20
= 200
(b)
Percent of the pens left unsold = 100% - 50% = 50% 50% of the pens that were sold = 10 u 50% of the pens that were left unsold = 10 u Percent of the pens left unsold that were blue = 60%
Percent of the pens left unsold that were green = 100% - 60% = 40%
Number of the pens left unsold that were green
= 40% x 10 u
=
40100 x 10 u
= 4 u
Number of green pens that Ryan had at first
= 4 u + 7 u
= 11 u
= 11 x 20
= 220
Answer(s): (a) 200; (b) 220
