2 days ago, Dana had a total of 300 grey and yellow coins. 20% of her coins were yellow coins. Today, her grandmother gave her some more coins. As a result, her grey coins increased by 10%. Now, 50% of her coins are yellow coins. How many yellow coins did her grandmother give her?
| |
Yellow coins |
Grey coins |
Total
coins |
| Before |
1 u |
4 u |
300 |
| Change |
+ 3.4 u |
+ 0.4 u |
|
| After |
4.4 u |
4.4 u |
|
Comparing the
grey coins and
yellow coins in the end |
1 |
1 |
|
20% =
20100 =
15 Yellow coins : Grey coins = 1 : 4
Increase in the number of grey coins
= 10% x 4 u
=
10100 x 4 u
= 0.4 u
50% =
50100 =
12 In the end
Yellow coins : Grey coins = 1 : 1
Number of coins at first
= 4 u + 1 u
= 5 u
5 u = 300
1 u = 300 ÷ 5 = 60
Number of yellow coins that Dana received from her grandmother
= 4.4 u - 1 u
= 3.4 u
= 3.4 x 60
= 204
Answer(s): 204
