Adam has some red stickers and blue stickers.
If Adam gives away 18 red stickers,
the red stickers will be 20% as many as the blue stickers.
If Adam gives away 120 blue stickers,
the red stickers will be 80% as many as the blue stickers.
- How many red stickers are there?
- How many blue stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Red |
Blue |
Red |
Blue |
Before |
1 u + 18 |
5 u |
4 p |
5 p + 120 |
Change |
- 18 |
No change |
No change |
- 120 |
After |
1 u |
5 u |
4 p |
5 p |
(a)
20% =
20100 =
15 80% =
80100 =
45 Scenario 1 Number of red stickers at first = 1 u + 18
Number of blue stickers at first = 5 u
Scenario 2 Number of red stickers at first = 4 p
Number of blue stickers at first = 5 p + 120
1 u + 18 = 4 p --- (1)
5 u = 5 p + 120 --- (2)
(1)
x 5 5 u + 90 = 20 p
5 u = 20 p - 90 --- (3)
(3) = (2)
20 p - 90 = 5 p + 120
20 p - 5 p = 90 + 120
15 p = 210
1 p = 210 ÷ 15 = 14
Number of red stickers
= 4 p
= 4 x 14
= 56
(b)
Number of blue stickers at first
= 5 p + 120
= 5 x 14 + 120
= 70 + 120
= 190
Answer(s): (a) 56; (b) 190