11 days ago, Julie had a total of 280 yellow and white buttons. 25% of her buttons were white buttons. Today, her younger sister gave her some more buttons. As a result, her yellow buttons increased by 30%. Now, 50% of her buttons are white buttons. How many white buttons did her younger sister give her?
| |
White buttons |
Yellow buttons |
Total
buttons |
| Before |
1 u |
3 u |
280 |
| Change |
+ 2.9 u |
+ 0.9 u |
|
| After |
3.9 u |
3.9 u |
|
Comparing the
yellow buttons and
white buttons in the end |
1 |
1 |
|
25% =
25100 =
14 White buttons : Yellow buttons = 1 : 3
Increase in the number of yellow buttons
= 30% x 3 u
=
30100 x 3 u
= 0.9 u
50% =
50100 =
12 In the end
White buttons : Yellow buttons = 1 : 1
Number of buttons at first
= 3 u + 1 u
= 4 u
4 u = 280
1 u = 280 ÷ 4 = 70
Number of white buttons that Julie received from her younger sister
= 3.9 u - 1 u
= 2.9 u
= 2.9 x 70
= 203
Answer(s): 203
