11 days ago, Nora had a total of 160 white and silver cards. 30% of her cards were silver cards. Today, her older sister gave her some more cards. As a result, her white cards increased by 25%. Now, 50% of her cards are silver cards. How many silver cards did her older sister give her?
| |
Silver cards |
White cards |
Total
cards |
| Before |
3 u |
7 u |
160 |
| Change |
+ 5.75 u |
+ 1.75 u |
|
| After |
8.75 u |
8.75 u |
|
Comparing the
white cards and
silver cards in the end |
1 |
1 |
|
30% =
30100 =
310 Silver cards : White cards = 3 : 7
Increase in the number of white cards
= 25% x 7 u
=
25100 x 7 u
= 1.75 u
50% =
50100 =
12 In the end
Silver cards : White cards = 1 : 1
Number of cards at first
= 7 u + 3 u
= 10 u
10 u = 160
1 u = 160 ÷ 10 = 16
Number of silver cards that Nora received from her older sister
= 8.75 u - 3 u
= 5.75 u
= 5.75 x 16
= 92
Answer(s): 92
