Adam has some red stickers and blue stickers.
If 197 red stickers are removed, 90% of the stickers will be blue stickers.
If 128 red stickers are added, 40% of the stickers will be blue stickers.
- How many red stickers are there?
- How many blue stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Red |
Blue |
Red |
Blue |
Before |
2 u + 197 |
18 u |
27 u - 128 |
18 u |
Change |
- 197 |
No change |
+ 128 |
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 red in the end
= 1 -
910 =
110 Scenario 2
Fraction of the stickers that are red in the end
= 1 -
25 =
35 The number of blue stickers remains unchanged in both scenarios.
LCM of 9 and 2 = 18
27 u - 128 = 2 u + 197
27 u - 2 u = 197 + 128
25 u = 325
1 u = 325 ÷ 25 = 13
Number of red stickers
= 2 u + 197
= 2 x 13 + 197
= 26 + 197
= 223
(b)
Number of blue stickers
= 18 u
= 18 x 13
= 234
Answer(s): (a) 223; (b) 234