Adam has some blue stickers and green stickers.
If Adam gives away 21 blue stickers,
the blue stickers will be 20% as many as the green stickers.
If Adam gives away 315 green stickers,
the blue stickers will be 80% as many as the green stickers.
- How many blue stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Green |
Blue |
Green |
Before |
1 u + 21 |
5 u |
4 p |
5 p + 315 |
Change |
- 21 |
No change |
No change |
- 315 |
After |
1 u |
5 u |
4 p |
5 p |
(a)
20% =
20100 =
15 80% =
80100 =
45 Scenario 1 Number of blue stickers at first = 1 u + 21
Number of green stickers at first = 5 u
Scenario 2 Number of blue stickers at first = 4 p
Number of green stickers at first = 5 p + 315
1 u + 21 = 4 p --- (1)
5 u = 5 p + 315 --- (2)
(1)
x 5 5 u + 105 = 20 p
5 u = 20 p - 105 --- (3)
(3) = (2)
20 p - 105 = 5 p + 315
20 p - 5 p = 105 + 315
15 p = 420
1 p = 420 ÷ 15 = 28
Number of blue stickers
= 4 p
= 4 x 28
= 112
(b)
Number of green stickers at first
= 5 p + 315
= 5 x 28 + 315
= 140 + 315
= 455
Answer(s): (a) 112; (b) 455