Adam has some green stickers and blue stickers.
If 140 green stickers are added, 40% of the stickers will be blue stickers.
If 100 blue stickers are added, 20% of the stickers will be green stickers.
- How many green stickers are there?
- How many blue stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Blue |
Green |
Blue |
Before |
3 u - 140 |
2 u |
1 p |
4 p - 100 |
Change |
+ 140 |
No change |
No change |
+ 100 |
After |
3 u |
2 u |
1 p |
4 p |
(a)
40% =
40100 =
25 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are green
= 1 -
25 =
35 Number of green stickers at first = 3 u - 140
Number of blue stickers at first = 2 u
Scenario 2 Fraction of the stickers that are blue
= 1 -
15=
45 Number of green stickers at first = 1 p
Number of blue stickers at first = 4 p - 100
3 u - 140 = 1 p --- (1)
2 u = 4 p - 100
2 u + 100 = 4 p --- (2)
(1)
x 4 12 u - 560 = 4 p --- (3)
(3) = (2)
12 u - 560 = 2 u + 100
12 u - 2 u = 560 + 100
10 u = 660
1 u = 660 ÷ 10 = 66
Number of green stickers
= 3 u - 140
= 3 x 66 - 140
= 198 - 140
= 58
(b)
Number of blue stickers
= 2 u
= 2 x 66
= 132
Answer(s): (a) 58; (b) 132