Adam has some blue stickers and red stickers.
If Adam gives away 39 blue stickers,
the blue stickers will be 25% as many as the red stickers.
If Adam gives away 12 red stickers,
the blue stickers will be 75% as many as the 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 + 39 |
4 u |
3 p |
4 p + 12 |
Change |
- 39 |
No change |
No change |
- 12 |
After |
1 u |
4 u |
3 p |
4 p |
(a)
25% =
25100 =
14 75% =
75100 =
34 Scenario 1 Number of blue stickers at first = 1 u + 39
Number of red stickers at first = 4 u
Scenario 2 Number of blue stickers at first = 3 p
Number of red stickers at first = 4 p + 12
1 u + 39 = 3 p --- (1)
4 u = 4 p + 12 --- (2)
(1)
x 4 4 u + 156 = 12 p
4 u = 12 p - 156 --- (3)
(3) = (2)
12 p - 156 = 4 p + 12
12 p - 4 p = 156 + 12
8 p = 168
1 p = 168 ÷ 8 = 21
Number of blue stickers
= 3 p
= 3 x 21
= 63
(b)
Number of red stickers at first
= 4 p + 12
= 4 x 21 + 12
= 84 + 12
= 96
Answer(s): (a) 63; (b) 96