14 days ago, Diana had a total of 240 grey and blue cards. 25% of her cards were blue cards. Today, her cousin gave her some more cards. As a result, her grey cards increased by 20%. Now, 50% of her cards are blue cards. How many blue cards did her cousin give her?
| |
Blue cards |
Grey cards |
Total
cards |
| Before |
1 u |
3 u |
240 |
| Change |
+ 2.6 u |
+ 0.6 u |
|
| After |
3.6 u |
3.6 u |
|
Comparing the
grey cards and
blue cards in the end |
1 |
1 |
|
25% =
25100 =
14 Blue cards : Grey cards = 1 : 3
Increase in the number of grey cards
= 20% x 3 u
=
20100 x 3 u
= 0.6 u
50% =
50100 =
12 In the end
Blue cards : Grey cards = 1 : 1
Number of cards at first
= 3 u + 1 u
= 4 u
4 u = 240
1 u = 240 ÷ 4 = 60
Number of blue cards that Diana received from her cousin
= 3.6 u - 1 u
= 2.6 u
= 2.6 x 60
= 156
Answer(s): 156
