Adam has some blue stickers and green stickers.
If 389 blue stickers are added, 30% of the stickers will be green stickers.
If 319 green stickers are added, 20% of the stickers will be blue stickers.
- How many blue stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Green |
Blue |
Green |
Before |
7 u - 389 |
3 u |
1 p |
4 p - 319 |
Change |
+ 389 |
No change |
No change |
+ 319 |
After |
7 u |
3 u |
1 p |
4 p |
(a)
30% =
30100 =
310 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are blue
= 1 -
310 =
710 Number of blue stickers at first = 7 u - 389
Number of green stickers at first = 3 u
Scenario 2 Fraction of the stickers that are green
= 1 -
15=
45 Number of blue stickers at first = 1 p
Number of green stickers at first = 4 p - 319
7 u - 389 = 1 p --- (1)
3 u = 4 p - 319
3 u + 319 = 4 p --- (2)
(1)
x 4 28 u - 1556 = 4 p --- (3)
(3) = (2)
28 u - 1556 = 3 u + 319
28 u - 3 u = 1556 + 319
25 u = 1875
1 u = 1875 ÷ 25 = 75
Number of blue stickers
= 7 u - 389
= 7 x 75 - 389
= 525 - 389
= 136
(b)
Number of green stickers
= 3 u
= 3 x 75
= 225
Answer(s): (a) 136; (b) 225