Adam has some green stickers and red stickers.
If 236 green stickers are added, 30% of the stickers will be red stickers.
If 390 red stickers are added, 25% 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 |
7 u - 236 |
3 u |
1 p |
3 p - 390 |
Change |
+ 236 |
No change |
No change |
+ 390 |
After |
7 u |
3 u |
1 p |
3 p |
(a)
30% =
30100 =
310 25% =
25100 =
14 Scenario 1 Fraction of the stickers that are green
= 1 -
310 =
710 Number of green stickers at first = 7 u - 236
Number of red stickers at first = 3 u
Scenario 2 Fraction of the stickers that are red
= 1 -
14=
34 Number of green stickers at first = 1 p
Number of red stickers at first = 3 p - 390
7 u - 236 = 1 p --- (1)
3 u = 3 p - 390
3 u + 390 = 3 p --- (2)
(1)
x 3 21 u - 708 = 3 p --- (3)
(3) = (2)
21 u - 708 = 3 u + 390
21 u - 3 u = 708 + 390
18 u = 1098
1 u = 1098 ÷ 18 = 61
Number of green stickers
= 7 u - 236
= 7 x 61 - 236
= 427 - 236
= 191
(b)
Number of red stickers
= 3 u
= 3 x 61
= 183
Answer(s): (a) 191; (b) 183