Adam has some blue stickers and green stickers.
If 150 blue stickers are removed, 90% of the stickers will be green stickers.
If 30 blue stickers are added, 30% of the stickers will be green stickers.
- How many blue stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Green |
Blue |
Green |
Before |
1 u + 150 |
9 u |
21 u - 30 |
9 u |
Change |
- 150 |
No change |
+ 30 |
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 blue in the end
= 1 -
910 =
110 Scenario 2
Fraction of the stickers that are blue in the end
= 1 -
310 =
710 The number of green stickers remains unchanged in both scenarios.
LCM of 9 and 3 = 9
21 u - 30 = 1 u + 150
21 u - 1 u = 150 + 30
20 u = 180
1 u = 180 ÷ 20 = 9
Number of blue stickers
= 1 u + 150
= 1 x 9 + 150
= 9 + 150
= 159
(b)
Number of green stickers
= 9 u
= 9 x 9
= 81
Answer(s): (a) 159; (b) 81