13 days ago, Fiona had a total of 280 grey and purple coins. 25% of her coins were purple coins. Today, her auntie gave her some more coins. As a result, her grey coins increased by 10%. Now, 50% of her coins are purple coins. How many purple coins did her auntie give her?
| |
Purple coins |
Grey coins |
Total
coins |
| Before |
1 u |
3 u |
280 |
| Change |
+ 2.3 u |
+ 0.3 u |
|
| After |
3.3 u |
3.3 u |
|
Comparing the
grey coins and
purple coins in the end |
1 |
1 |
|
25% =
25100 =
14 Purple coins : Grey coins = 1 : 3
Increase in the number of grey coins
= 10% x 3 u
=
10100 x 3 u
= 0.3 u
50% =
50100 =
12 In the end
Purple coins : Grey coins = 1 : 1
Number of coins at first
= 3 u + 1 u
= 4 u
4 u = 280
1 u = 280 ÷ 4 = 70
Number of purple coins that Fiona received from her auntie
= 3.3 u - 1 u
= 2.3 u
= 2.3 x 70
= 161
Answer(s): 161
