12 days ago, Jen had a total of 275 black and purple buttons. 20% of her buttons were purple buttons. Today, her younger sister gave her some more buttons. As a result, her black buttons increased by 40%. Now, 50% of her buttons are purple buttons. How many purple buttons did her younger sister give her?
| |
Purple buttons |
Black buttons |
Total
buttons |
| Before |
1 u |
4 u |
275 |
| Change |
+ 4.6 u |
+ 1.6 u |
|
| After |
5.6 u |
5.6 u |
|
Comparing the
black buttons and
purple buttons in the end |
1 |
1 |
|
20% =
20100 =
15 Purple buttons : Black buttons = 1 : 4
Increase in the number of black buttons
= 40% x 4 u
=
40100 x 4 u
= 1.6 u
50% =
50100 =
12 In the end
Purple buttons : Black buttons = 1 : 1
Number of buttons at first
= 4 u + 1 u
= 5 u
5 u = 275
1 u = 275 ÷ 5 = 55
Number of purple buttons that Jen received from her younger sister
= 5.6 u - 1 u
= 4.6 u
= 4.6 x 55
= 253
Answer(s): 253
