Adam has some green stickers and blue stickers.
If 393 green stickers are removed, 90% of the stickers will be blue stickers.
If 107 green stickers are added, 30% of the stickers will be blue stickers.
- How many green stickers are there?
- How many blue stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Blue |
Green |
Blue |
Before |
1 u + 393 |
9 u |
21 u - 107 |
9 u |
Change |
- 393 |
No change |
+ 107 |
No change |
After |
1x1 = 1 u |
9x1 = 9 u |
7x3 = 21 u |
3x3 = 9 u |
(a)
90% =
90100 =
91030% =
30100 =
310Scenario 1 Fraction of the stickers that are green in the end
= 1 -
910 =
110 Scenario 2
Fraction of the stickers that are green in the end
= 1 -
310 =
710 The number of blue stickers remains unchanged in both scenarios.
LCM of 9 and 3 = 9
21 u - 107 = 1 u + 393
21 u - 1 u = 393 + 107
20 u = 500
1 u = 500 ÷ 20 = 25
Number of green stickers
= 1 u + 393
= 1 x 25 + 393
= 25 + 393
= 418
(b)
Number of blue stickers
= 9 u
= 9 x 25
= 225
Answer(s): (a) 418; (b) 225