Adam has some blue stickers and red stickers.
If 65 blue stickers are removed, 80% of the stickers will be red stickers.
If 578 red stickers are added, 30% of the stickers will be blue stickers.
- How many blue stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Red |
Blue |
Red |
Before |
1 u + 65 |
4 u |
3 p |
7 p - 578 |
Change |
- 65 |
No change |
No change |
+ 578 |
After |
1 u |
4 u |
3 p |
7 p |
(a)
80% =
80100
=
45 30% =
30100 =
310 Scenario 1 Fraction of the stickers that are blue in the end
= 1 -
45 =
15 Scenario 2
Fraction of the stickers that are blue in the end
= 1 -
310 =
710 1 u + 65 = 3 p --- (1)
4 u = 7 p - 578 --- (2)
(1)
x 4 4 u + 260 = 4 p
4 u = 4 p - 260 --- (3)
(2) = (3)
7 p - 578 = 4 p - 260
7 p - 4 p = 578 - 260
3 p = 318
1 p = 318 ÷ 3 = 106
Number of blue stickers
= 3 p
= 3 x 106
= 318
(b)
Number of red stickers
= 7 p - 578
= 7 x 106 - 578
= 742 - 578
= 164
Answer(s): (a) 318; (b) 164