8 days ago, Nicole had a total of 100 grey and gold buttons. 30% of her buttons were gold buttons. Today, her father gave her some more buttons. As a result, her grey buttons increased by 10%. Now, 50% of her buttons are gold buttons. How many gold buttons did her father give her?
| |
Gold buttons |
Grey buttons |
Total
buttons |
| Before |
3 u |
7 u |
100 |
| Change |
+ 4.7 u |
+ 0.7 u |
|
| After |
7.7 u |
7.7 u |
|
Comparing the
grey buttons and
gold buttons in the end |
1 |
1 |
|
30% =
30100 =
310 Gold buttons : Grey buttons = 3 : 7
Increase in the number of grey buttons
= 10% x 7 u
=
10100 x 7 u
= 0.7 u
50% =
50100 =
12 In the end
Gold buttons : Grey buttons = 1 : 1
Number of buttons at first
= 7 u + 3 u
= 10 u
10 u = 100
1 u = 100 ÷ 10 = 10
Number of gold buttons that Nicole received from her father
= 7.7 u - 3 u
= 4.7 u
= 4.7 x 10
= 47
Answer(s): 47
