PSLE Ahmad had yellow pens and blue pens for sale. He sold 60 yellow pens. 70% of the pens sold were blue.
- How many yellow pens and blue pens did Ahmad sell altogether?
- He sold 50% of his pens. 70% of the pens left unsold were yellow. How many blue pens did Ahmad have at first?
|
Yellow |
Blue |
Total |
Total in percent |
Before |
10 u |
10 u |
20 u |
100% |
Change |
- 30% - 3 u |
- 70% - 7 u |
- 100% - 10 u |
- 50% |
After |
70% 7 u |
30% 3 u |
100% 10 u |
50%
|
70% =
70100 =
710 Total number of pens sold = 10 u
Number of blue pens sold = 7 u
Number of yellow 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 yellow = 70%
Percent of the pens left unsold that were blue = 100% - 70% = 30%
Number of the pens left unsold that were blue
= 30% x 10 u
=
30100 x 10 u
= 3 u
Number of blue pens that Ahmad had at first
= 3 u + 7 u
= 10 u
= 10 x 20
= 200
Answer(s): (a) 200; (b) 200