Adam has some red stickers and green stickers.
If 34 red stickers are added, 70% of the stickers will be green stickers.
If 394 red stickers are added, 30% of the stickers will be green stickers.
- How many red stickers are there?
- How many green stickers are there?
|
Scenario 1 |
Scenario 2 |
|
Red |
Green |
Red |
Green |
Before |
9 u - 34 |
21 u |
49 u - 394 |
21 u |
Change |
+ 34 |
No change |
+ 394 |
No change |
After |
3x3 = 9 u |
7x3 = 21 u |
7x7 = 49 u |
3x7 = 21 u |
(a)
70% =
70100 =
71030% =
30100 =
310 Scenario 1 Fraction of the stickers that are red in the end
= 1 -
710 =
310 Scenario 2
Fraction of the stickers that are red in the end
= 1 -
310 =
710 The number of green stickers remains unchanged in both scenarios.
LCM of 7 and 3 = 21
49 u - 394 = 9 u - 34
49 u - 9 u = 394 - 34
40 u = 360
1 u = 360 ÷ 40 = 9
Number of red stickers
= 9 u - 34
= 9 x 9 - 34
= 81 - 34
= 47
(b)
Number of green stickers
= 21 u
= 21 x 9
= 189
Answer(s): (a) 47; (b) 189