Adam has some blue stickers and green stickers.
If 30 blue stickers are added, 70% of the stickers will be green stickers.
If 380 blue stickers are added, 20% of the stickers will be green stickers.
- How many blue stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Blue |
Green |
Blue |
Green |
Before |
3 u - 30 |
7 u |
28 u - 380 |
7 u |
Change |
+ 30 |
No change |
+ 380 |
No change |
After |
3x1 = 3 u |
7x1 = 7 u |
4x7 = 28 u |
1x7 = 7 u |
(a)
70% =
70100 =
71020% =
20100 =
15 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 -
15 =
45 The number of green stickers remains unchanged in both scenarios.
LCM of 7 and 1 = 7
28 u - 380 = 3 u - 30
28 u - 3 u = 380 - 30
25 u = 350
1 u = 350 ÷ 25 = 14
Number of blue stickers
= 3 u - 30
= 3 x 14 - 30
= 42 - 30
= 12
(b)
Number of green stickers
= 7 u
= 7 x 14
= 98
Answer(s): (a) 12; (b) 98