4 days ago, Barbara had a total of 250 green and pink cards. 40% of her cards were pink cards. Today, her older sister gave her some more cards. As a result, her green cards increased by 20%. Now, 50% of her cards are pink cards. How many pink cards did her older sister give her?
| |
Pink cards |
Green cards |
Total
cards |
| Before |
2 u |
3 u |
250 |
| Change |
+ 1.6 u |
+ 0.6 u |
|
| After |
3.6 u |
3.6 u |
|
Comparing the
green cards and
pink cards in the end |
1 |
1 |
|
40% =
40100 =
25 Pink cards : Green cards = 2 : 3
Increase in the number of green cards
= 20% x 3 u
=
20100 x 3 u
= 0.6 u
50% =
50100 =
12 In the end
Pink cards : Green cards = 1 : 1
Number of cards at first
= 3 u + 2 u
= 5 u
5 u = 250
1 u = 250 ÷ 5 = 50
Number of pink cards that Barbara received from her older sister
= 3.6 u - 2 u
= 1.6 u
= 1.6 x 50
= 80
Answer(s): 80
