Risa had some card collection.
12 of them were blue and the rest were silver. She gave away 195 of the silver cards and 20% of the blue cards. She then had
14 of her card collection left. How many cards did Risa give away?
| |
Blue |
Silver |
Total |
Total |
Before
|
1x2 =
2 u |
1x2 =
2 u |
2x2 =
4 u |
4x1 =
4 u |
Change
|
- 0.2x2 =
- 0.4 u |
- 195 |
|
- 3x1 =
- 3 u |
After
|
0.8x2 =
1.6 u |
2 u - 195 |
|
1x1 =
1 u |
The total number of cards that Risa had at first is repeated. Make the total number of cards at first the same. LCM 2 and 4 is 4.
Number of blue cards that Risa gave away
= 20% x 1 u
=
20100 x 1 u
= 0.2 u
0.4 u - 195 = 3 u
3 u - 0.4 u = 195
2.6 u = 195
1 u = 195 ÷ 2.6 = 75
Number of cards that Risa gave away
= 3 u
= 3 x 75
= 225
Answer(s): 225
