10 days ago, Olivia had a total of 200 red and grey stickers. 30% of her stickers were grey stickers. Today, her auntie gave her some more stickers. As a result, her red stickers increased by 10%. Now, 50% of her stickers are grey stickers. How many grey stickers did her auntie give her?
| |
Grey stickers |
Red stickers |
Total
stickers |
| Before |
3 u |
7 u |
200 |
| Change |
+ 4.7 u |
+ 0.7 u |
|
| After |
7.7 u |
7.7 u |
|
Comparing the
red stickers and
grey stickers in the end |
1 |
1 |
|
30% =
30100 =
310 Grey stickers : Red stickers = 3 : 7
Increase in the number of red stickers
= 10% x 7 u
=
10100 x 7 u
= 0.7 u
50% =
50100 =
12 In the end
Grey stickers : Red stickers = 1 : 1
Number of stickers at first
= 7 u + 3 u
= 10 u
10 u = 200
1 u = 200 ÷ 10 = 20
Number of grey stickers that Olivia received from her auntie
= 7.7 u - 3 u
= 4.7 u
= 4.7 x 20
= 94
Answer(s): 94
