5 days ago, Kathy had a total of 125 yellow and blue coins. 20% of her coins were blue coins. Today, her younger brother gave her some more coins. As a result, her yellow coins increased by 30%. Now, 50% of her coins are blue coins. How many blue coins did her younger brother give her?
| |
Blue coins |
Yellow coins |
Total
coins |
| Before |
1 u |
4 u |
125 |
| Change |
+ 4.2 u |
+ 1.2 u |
|
| After |
5.2 u |
5.2 u |
|
Comparing the
yellow coins and
blue coins in the end |
1 |
1 |
|
20% =
20100 =
15 Blue coins : Yellow coins = 1 : 4
Increase in the number of yellow coins
= 30% x 4 u
=
30100 x 4 u
= 1.2 u
50% =
50100 =
12 In the end
Blue coins : Yellow coins = 1 : 1
Number of coins at first
= 4 u + 1 u
= 5 u
5 u = 125
1 u = 125 ÷ 5 = 25
Number of blue coins that Kathy received from her younger brother
= 5.2 u - 1 u
= 4.2 u
= 4.2 x 25
= 105
Answer(s): 105
