Adam has some red stickers and blue stickers.
If Adam gives away 31 red stickers,
the red stickers will be 20% as many as the blue stickers.
If Adam gives away 115 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 + 31 |
5 u |
4 p |
5 p + 115 |
Change |
- 31 |
No change |
No change |
- 115 |
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 + 31
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 + 115
1 u + 31 = 4 p --- (1)
5 u = 5 p + 115 --- (2)
(1)
x 5 5 u + 155 = 20 p
5 u = 20 p - 155 --- (3)
(3) = (2)
20 p - 155 = 5 p + 115
20 p - 5 p = 155 + 115
15 p = 270
1 p = 270 ÷ 15 = 18
Number of red stickers
= 4 p
= 4 x 18
= 72
(b)
Number of blue stickers at first
= 5 p + 115
= 5 x 18 + 115
= 90 + 115
= 205
Answer(s): (a) 72; (b) 205