Adam has some blue stickers and green stickers.
If 392 blue stickers are added, 30% of the stickers will be green stickers.
If 252 green stickers are added, 10% 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 - 392 |
3 u |
1 p |
9 p - 252 |
Change |
+ 392 |
No change |
No change |
+ 252 |
After |
7 u |
3 u |
1 p |
9 p |
(a)
30% =
30100 =
310 10% =
10100 =
110 Scenario 1 Fraction of the stickers that are blue
= 1 -
310 =
710 Number of blue stickers at first = 7 u - 392
Number of green stickers at first = 3 u
Scenario 2 Fraction of the stickers that are green
= 1 -
110=
910 Number of blue stickers at first = 1 p
Number of green stickers at first = 9 p - 252
7 u - 392 = 1 p --- (1)
3 u = 9 p - 252
3 u + 252 = 9 p --- (2)
(1)
x 9 63 u - 3528 = 9 p --- (3)
(3) = (2)
63 u - 3528 = 3 u + 252
63 u - 3 u = 3528 + 252
60 u = 3780
1 u = 3780 ÷ 60 = 63
Number of blue stickers
= 7 u - 392
= 7 x 63 - 392
= 441 - 392
= 49
(b)
Number of green stickers
= 3 u
= 3 x 63
= 189
Answer(s): (a) 49; (b) 189