Adam has some red stickers and green stickers.
If 238 red stickers are added, 30% of the stickers will be green stickers.
If 298 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 - 238 |
3 u |
1 p |
4 p - 298 |
Change |
+ 238 |
No change |
No change |
+ 298 |
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 - 238
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 - 298
7 u - 238 = 1 p --- (1)
3 u = 4 p - 298
3 u + 298 = 4 p --- (2)
(1)
x 4 28 u - 952 = 4 p --- (3)
(3) = (2)
28 u - 952 = 3 u + 298
28 u - 3 u = 952 + 298
25 u = 1250
1 u = 1250 ÷ 25 = 50
Number of red stickers
= 7 u - 238
= 7 x 50 - 238
= 350 - 238
= 112
(b)
Number of green stickers
= 3 u
= 3 x 50
= 150
Answer(s): (a) 112; (b) 150