Eva had some card collection.
37 of them were red and the rest were silver. She gave away 140 of the silver cards and 50% of the red cards. She then had
23 of her card collection left. How many cards did Eva give away?
| |
Red |
Silver |
Total |
Total |
Before
|
3x3 =
9 u |
4x3 =
12 u |
7x3 =
21 u |
3x7 =
21 u |
Change
|
- 1.5x3 =
- 4.5 u |
- 140 |
|
- 1x7 =
- 7 u |
After
|
1.5x3 =
4.5 u |
12 u - 140 |
|
2x7 =
14 u |
The total number of cards that Eva had at first is repeated. Make the total number of cards at first the same. LCM 7 and 3 is 21.
Number of red cards that Eva gave away
= 50% x 3 u
=
50100 x 3 u
= 1.5 u
4.5 u - 140 = 7 u
7 u - 4.5 u = 140
2.5 u = 140
1 u = 140 ÷ 2.5 = 56
Number of cards that Eva gave away
= 7 u
= 7 x 56
= 392
Answer(s): 392
