Adam has some red stickers and blue stickers.
If 340 red stickers are added, 40% of the stickers will be blue stickers.
If 180 blue stickers are added, 20% of the stickers will be red stickers.
- How many red stickers are there?
- How many blue stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Red |
Blue |
Red |
Blue |
Before |
3 u - 340 |
2 u |
1 p |
4 p - 180 |
Change |
+ 340 |
No change |
No change |
+ 180 |
After |
3 u |
2 u |
1 p |
4 p |
(a)
40% =
40100 =
25 20% =
20100 =
15 Scenario 1 Fraction of the stickers that are red
= 1 -
25 =
35 Number of red stickers at first = 3 u - 340
Number of blue stickers at first = 2 u
Scenario 2 Fraction of the stickers that are blue
= 1 -
15=
45 Number of red stickers at first = 1 p
Number of blue stickers at first = 4 p - 180
3 u - 340 = 1 p --- (1)
2 u = 4 p - 180
2 u + 180 = 4 p --- (2)
(1)
x 4 12 u - 1360 = 4 p --- (3)
(3) = (2)
12 u - 1360 = 2 u + 180
12 u - 2 u = 1360 + 180
10 u = 1540
1 u = 1540 ÷ 10 = 154
Number of red stickers
= 3 u - 340
= 3 x 154 - 340
= 462 - 340
= 122
(b)
Number of blue stickers
= 2 u
= 2 x 154
= 308
Answer(s): (a) 122; (b) 308