9 days ago, Gillian had a total of 250 blue and brown coins. 30% of her coins were brown coins. Today, her auntie gave her some more coins. As a result, her blue coins increased by 40%. Now, 50% of her coins are brown coins. How many brown coins did her auntie give her?
| |
Brown coins |
Blue coins |
Total
coins |
| Before |
3 u |
7 u |
250 |
| Change |
+ 6.8 u |
+ 2.8 u |
|
| After |
9.8 u |
9.8 u |
|
Comparing the
blue coins and
brown coins in the end |
1 |
1 |
|
30% =
30100 =
310 Brown coins : Blue coins = 3 : 7
Increase in the number of blue coins
= 40% x 7 u
=
40100 x 7 u
= 2.8 u
50% =
50100 =
12 In the end
Brown coins : Blue coins = 1 : 1
Number of coins at first
= 7 u + 3 u
= 10 u
10 u = 250
1 u = 250 ÷ 10 = 25
Number of brown coins that Gillian received from her auntie
= 9.8 u - 3 u
= 6.8 u
= 6.8 x 25
= 170
Answer(s): 170
