Adam has some blue stickers and red stickers.
If 36 blue stickers are added, 70% of the stickers will be red stickers.
If 216 blue stickers are added, 40% of the stickers will be red stickers.
- How many blue stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Red |
Blue |
Red |
Before |
6 u - 36 |
14 u |
21 u - 216 |
14 u |
Change |
+ 36 |
No change |
+ 216 |
No change |
After |
3x2 = 6 u |
7x2 = 14 u |
3x7 = 21 u |
2x7 = 14 u |
(a)
70% =
70100 =
71040% =
40100 =
25 Scenario 1 Fraction of the stickers that are blue in the end
= 1 -
710 =
310 Scenario 2
Fraction of the stickers that are blue in the end
= 1 -
25 =
35 The number of red stickers remains unchanged in both scenarios.
LCM of 7 and 2 = 14
21 u - 216 = 6 u - 36
21 u - 6 u = 216 - 36
15 u = 180
1 u = 180 ÷ 15 = 12
Number of blue stickers
= 6 u - 36
= 6 x 12 - 36
= 72 - 36
= 36
(b)
Number of red stickers
= 14 u
= 14 x 12
= 168
Answer(s): (a) 36; (b) 168