Adam has some green stickers and red stickers.
If 39 green stickers are removed, 80% of the stickers will be red stickers.
If 491 red stickers are added, 10% of the stickers will be green stickers.
- How many green stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Red |
Green |
Red |
Before |
1 u + 39 |
4 u |
1 p |
9 p - 491 |
Change |
- 39 |
No change |
No change |
+ 491 |
After |
1 u |
4 u |
1 p |
9 p |
(a)
80% =
80100
=
45 10% =
10100 =
110 Scenario 1 Fraction of the stickers that are green in the end
= 1 -
45 =
15 Scenario 2
Fraction of the stickers that are green in the end
= 1 -
110 =
910 1 u + 39 = 1 p --- (1)
4 u = 9 p - 491 --- (2)
(1)
x 4 4 u + 156 = 4 p
4 u = 4 p - 156 --- (3)
(2) = (3)
9 p - 491 = 4 p - 156
9 p - 4 p = 491 - 156
5 p = 335
1 p = 335 ÷ 5 = 67
Number of green stickers
= 1 p
= 1 x 67
= 67
(b)
Number of red stickers
= 9 p - 491
= 9 x 67 - 491
= 603 - 491
= 112
Answer(s): (a) 67; (b) 112