Adam has some blue stickers and red stickers.
If 275 blue stickers are added, 30% of the stickers will be red stickers.
If 363 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 - 275 |
3 u |
1 p |
3 p - 363 |
Change |
+ 275 |
No change |
No change |
+ 363 |
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 - 275
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 - 363
7 u - 275 = 1 p --- (1)
3 u = 3 p - 363
3 u + 363 = 3 p --- (2)
(1)
x 3 21 u - 825 = 3 p --- (3)
(3) = (2)
21 u - 825 = 3 u + 363
21 u - 3 u = 825 + 363
18 u = 1188
1 u = 1188 ÷ 18 = 66
Number of blue stickers
= 7 u - 275
= 7 x 66 - 275
= 462 - 275
= 187
(b)
Number of red stickers
= 3 u
= 3 x 66
= 198
Answer(s): (a) 187; (b) 198