Adam has some green stickers and red stickers.
If 22 green stickers are added, 70% of the stickers will be red stickers.
If 222 green stickers are added, 20% of the stickers will be red stickers.
- How many green stickers are there?
- How many red stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Green |
Red |
Green |
Red |
Before |
3 u - 22 |
7 u |
28 u - 222 |
7 u |
Change |
+ 22 |
No change |
+ 222 |
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 green in the end
= 1 -
710 =
310 Scenario 2
Fraction of the stickers that are green in the end
= 1 -
15 =
45 The number of red stickers remains unchanged in both scenarios.
LCM of 7 and 1 = 7
28 u - 222 = 3 u - 22
28 u - 3 u = 222 - 22
25 u = 200
1 u = 200 ÷ 25 = 8
Number of green stickers
= 3 u - 22
= 3 x 8 - 22
= 24 - 22
= 2
(b)
Number of red stickers
= 7 u
= 7 x 8
= 56
Answer(s): (a) 2; (b) 56