Adam has some red stickers and green stickers.
If 150 red stickers are added, 30% of the stickers will be green stickers.
If 125 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 |
7 u - 150 |
3 u |
1 p |
4 p - 125 |
Change |
+ 150 |
No change |
No change |
+ 125 |
After |
7 u |
3 u |
1 p |
4 p |
(a)
30% =
30100 =
310 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are red
= 1 -
310 =
710 Number of red stickers at first = 7 u - 150
Number of green stickers at first = 3 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 - 125
7 u - 150 = 1 p --- (1)
3 u = 4 p - 125
3 u + 125 = 4 p --- (2)
(1)
x 4 28 u - 600 = 4 p --- (3)
(3) = (2)
28 u - 600 = 3 u + 125
28 u - 3 u = 600 + 125
25 u = 725
1 u = 725 ÷ 25 = 29
Number of red stickers
= 7 u - 150
= 7 x 29 - 150
= 203 - 150
= 53
(b)
Number of green stickers
= 3 u
= 3 x 29
= 87
Answer(s): (a) 53; (b) 87