Adam has some green stickers and red stickers.
If 69 green stickers are removed, 75% of the stickers will be red stickers.
If 579 red stickers are added, 30% 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 + 69 |
3 u |
3 p |
7 p - 579 |
Change |
- 69 |
No change |
No change |
+ 579 |
After |
1 u |
3 u |
3 p |
7 p |
(a)
75% =
75100
=
34 30% =
30100 =
310 Scenario 1 Fraction of the stickers that are green in the end
= 1 -
34 =
14 Scenario 2
Fraction of the stickers that are green in the end
= 1 -
310 =
710 1 u + 69 = 3 p --- (1)
3 u = 7 p - 579 --- (2)
(1)
x 3 3 u + 207 = 3 p
3 u = 3 p - 207 --- (3)
(2) = (3)
7 p - 579 = 3 p - 207
7 p - 3 p = 579 - 207
4 p = 372
1 p = 372 ÷ 4 = 93
Number of green stickers
= 3 p
= 3 x 93
= 279
(b)
Number of red stickers
= 7 p - 579
= 7 x 93 - 579
= 651 - 579
= 72
Answer(s): (a) 279; (b) 72