Adam has some green stickers and red stickers.
If 69 green stickers are removed, 90% of the stickers will be red stickers.
If 106 green stickers are added, 40% of the stickers will be red stickers.
- How many green stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Red |
Green |
Red |
Before |
2 u + 69 |
18 u |
27 u - 106 |
18 u |
Change |
- 69 |
No change |
+ 106 |
No change |
After |
1x2 = 2 u |
9x2 = 18 u |
3x9 = 27 u |
2x9 = 18 u |
(a)
90% =
90100 =
91040% =
40100 =
25Scenario 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 -
25 =
35 The number of red stickers remains unchanged in both scenarios.
LCM of 9 and 2 = 18
27 u - 106 = 2 u + 69
27 u - 2 u = 69 + 106
25 u = 175
1 u = 175 ÷ 25 = 7
Number of green stickers
= 2 u + 69
= 2 x 7 + 69
= 14 + 69
= 83
(b)
Number of red stickers
= 18 u
= 18 x 7
= 126
Answer(s): (a) 83; (b) 126