Adam has some blue stickers and red stickers.
If 20 blue stickers are removed, 80% of the stickers will be red stickers.
If 425 red stickers are added, 10% 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 + 20 |
4 u |
1 p |
9 p - 425 |
Change |
- 20 |
No change |
No change |
+ 425 |
After |
1 u |
4 u |
1 p |
9 p |
(a)
80% =
80100
=
45 10% =
10100 =
110 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 -
110 =
910 1 u + 20 = 1 p --- (1)
4 u = 9 p - 425 --- (2)
(1)
x 4 4 u + 80 = 4 p
4 u = 4 p - 80 --- (3)
(2) = (3)
9 p - 425 = 4 p - 80
9 p - 4 p = 425 - 80
5 p = 345
1 p = 345 ÷ 5 = 69
Number of blue stickers
= 1 p
= 1 x 69
= 69
(b)
Number of red stickers
= 9 p - 425
= 9 x 69 - 425
= 621 - 425
= 196
Answer(s): (a) 69; (b) 196