12 days ago, Wendy had a total of 225 purple and blue cards. 20% of her cards were blue cards. Today, her grandmother gave her some more cards. As a result, her purple cards increased by 30%. Now, 50% of her cards are blue cards. How many blue cards did her grandmother give her?
| |
Blue cards |
Purple cards |
Total
cards |
| Before |
1 u |
4 u |
225 |
| Change |
+ 4.2 u |
+ 1.2 u |
|
| After |
5.2 u |
5.2 u |
|
Comparing the
purple cards and
blue cards in the end |
1 |
1 |
|
20% =
20100 =
15 Blue cards : Purple cards = 1 : 4
Increase in the number of purple cards
= 30% x 4 u
=
30100 x 4 u
= 1.2 u
50% =
50100 =
12 In the end
Blue cards : Purple cards = 1 : 1
Number of cards at first
= 4 u + 1 u
= 5 u
5 u = 225
1 u = 225 ÷ 5 = 45
Number of blue cards that Wendy received from her grandmother
= 5.2 u - 1 u
= 4.2 u
= 4.2 x 45
= 189
Answer(s): 189
