Adam has some blue stickers and red stickers.
If 140 blue stickers are removed, 20% of the stickers will be blue stickers.
If 140 red stickers are removed, 10% of the stickers will be red stickers.
- How many blue stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Red |
Blue |
Red |
Before |
1 u + 140 |
4 u |
9 p |
1 p + 140 |
Change |
- 140 |
No change |
No change |
- 140 |
After |
1 u |
4 u |
9 p |
1 p |
(a)
20% =
20100 =
15 10% =
10100 =
110 Scenario 1Fraction of the stickers that are red
= 1 -
15 =
45 Scenario 2Fraction of the stickers that are blue
= 1 -
110 =
9101 u + 140 = 9 p --- (1)
4 u = 1 p + 140 --- (2)
From (1)
1 u = 9 p - 140 --- (3)
(3)
x 44 u = 36 p - 560 --- (4)
(4) = (2)
36 p - 560 = 1 p + 140
36 p - 1 p = 560 + 140
35 p = 700
1 p = 700 ÷ 35 = 20Number of blue stickers = 9 p
= 9 x 20= 180 (b) Number of red stickers = 1 p + 140 = 20 + 140 = 160 Answer(s): (a) 180; (b) 160