Adam has some red stickers and green stickers.
If 115 red stickers are added, 40% of the stickers will be green stickers.
If 110 green stickers are added, 20% of the stickers will be red stickers.
- How many red stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Red |
Green |
Red |
Green |
Before |
3 u - 115 |
2 u |
1 p |
4 p - 110 |
Change |
+ 115 |
No change |
No change |
+ 110 |
After |
3 u |
2 u |
1 p |
4 p |
(a)
40% =
40100 =
25 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are red
= 1 -
25 =
35 Number of red stickers at first = 3 u - 115
Number of green stickers at first = 2 u
Scenario 2 Fraction of the stickers that are green
= 1 -
15=
45 Number of red stickers at first = 1 p
Number of green stickers at first = 4 p - 110
3 u - 115 = 1 p --- (1)
2 u = 4 p - 110
2 u + 110 = 4 p --- (2)
(1)
x 4 12 u - 460 = 4 p --- (3)
(3) = (2)
12 u - 460 = 2 u + 110
12 u - 2 u = 460 + 110
10 u = 570
1 u = 570 ÷ 10 = 57
Number of red stickers
= 3 u - 115
= 3 x 57 - 115
= 171 - 115
= 56
(b)
Number of green stickers
= 2 u
= 2 x 57
= 114
Answer(s): (a) 56; (b) 114