6 days ago, Penelope had a total of 120 red and yellow stickers. 30% of her stickers were yellow stickers. Today, her uncle gave her some more stickers. As a result, her red stickers increased by 25%. Now, 50% of her stickers are yellow stickers. How many yellow stickers did her uncle give her?
| |
Yellow stickers |
Red stickers |
Total
stickers |
| Before |
3 u |
7 u |
120 |
| Change |
+ 5.75 u |
+ 1.75 u |
|
| After |
8.75 u |
8.75 u |
|
Comparing the
red stickers and
yellow stickers in the end |
1 |
1 |
|
30% =
30100 =
310 Yellow stickers : Red stickers = 3 : 7
Increase in the number of red stickers
= 25% x 7 u
=
25100 x 7 u
= 1.75 u
50% =
50100 =
12 In the end
Yellow stickers : Red stickers = 1 : 1
Number of stickers at first
= 7 u + 3 u
= 10 u
10 u = 120
1 u = 120 ÷ 10 = 12
Number of yellow stickers that Penelope received from her uncle
= 8.75 u - 3 u
= 5.75 u
= 5.75 x 12
= 69
Answer(s): 69
