Adam has some green stickers and red stickers.
If 160 green stickers are added, 40% of the stickers will be red stickers.
If 300 red stickers are added, 20% of the stickers will be green stickers.
- How many green stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Red |
Green |
Red |
Before |
3 u - 160 |
2 u |
1 p |
4 p - 300 |
Change |
+ 160 |
No change |
No change |
+ 300 |
After |
3 u |
2 u |
1 p |
4 p |
(a)
40% =
40100 =
25 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are green
= 1 -
25 =
35 Number of green stickers at first = 3 u - 160
Number of red stickers at first = 2 u
Scenario 2 Fraction of the stickers that are red
= 1 -
15=
45 Number of green stickers at first = 1 p
Number of red stickers at first = 4 p - 300
3 u - 160 = 1 p --- (1)
2 u = 4 p - 300
2 u + 300 = 4 p --- (2)
(1)
x 4 12 u - 640 = 4 p --- (3)
(3) = (2)
12 u - 640 = 2 u + 300
12 u - 2 u = 640 + 300
10 u = 940
1 u = 940 ÷ 10 = 94
Number of green stickers
= 3 u - 160
= 3 x 94 - 160
= 282 - 160
= 122
(b)
Number of red stickers
= 2 u
= 2 x 94
= 188
Answer(s): (a) 122; (b) 188