12 days ago, Vanessa had a total of 150 pink and blue coins. 30% of her coins were blue coins. Today, her older sister gave her some more coins. As a result, her pink coins increased by 20%. Now, 50% of her coins are blue coins. How many blue coins did her older sister give her?
| |
Blue coins |
Pink coins |
Total
coins |
| Before |
3 u |
7 u |
150 |
| Change |
+ 5.4 u |
+ 1.4 u |
|
| After |
8.4 u |
8.4 u |
|
Comparing the
pink coins and
blue coins in the end |
1 |
1 |
|
30% =
30100 =
310 Blue coins : Pink coins = 3 : 7
Increase in the number of pink coins
= 20% x 7 u
=
20100 x 7 u
= 1.4 u
50% =
50100 =
12 In the end
Blue coins : Pink coins = 1 : 1
Number of coins at first
= 7 u + 3 u
= 10 u
10 u = 150
1 u = 150 ÷ 10 = 15
Number of blue coins that Vanessa received from her older sister
= 8.4 u - 3 u
= 5.4 u
= 5.4 x 15
= 81
Answer(s): 81
