Adam has some blue stickers and red stickers.
If 186 blue stickers are added, 30% of the stickers will be red stickers.
If 234 red stickers are added, 25% of the stickers will be blue stickers.
- How many blue stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Red |
Blue |
Red |
Before |
7 u - 186 |
3 u |
1 p |
3 p - 234 |
Change |
+ 186 |
No change |
No change |
+ 234 |
After |
7 u |
3 u |
1 p |
3 p |
(a)
30% =
30100 =
310 25% =
25100 =
14 Scenario 1 Fraction of the stickers that are blue
= 1 -
310 =
710 Number of blue stickers at first = 7 u - 186
Number of red stickers at first = 3 u
Scenario 2 Fraction of the stickers that are red
= 1 -
14=
34 Number of blue stickers at first = 1 p
Number of red stickers at first = 3 p - 234
7 u - 186 = 1 p --- (1)
3 u = 3 p - 234
3 u + 234 = 3 p --- (2)
(1)
x 3 21 u - 558 = 3 p --- (3)
(3) = (2)
21 u - 558 = 3 u + 234
21 u - 3 u = 558 + 234
18 u = 792
1 u = 792 ÷ 18 = 44
Number of blue stickers
= 7 u - 186
= 7 x 44 - 186
= 308 - 186
= 122
(b)
Number of red stickers
= 3 u
= 3 x 44
= 132
Answer(s): (a) 122; (b) 132