Erika had some coin collection.
29 of them were grey and the rest were purple. She gave away 196 of the purple coins and 20% of the grey coins. She then had
13 of her coin collection left. How many coins did Erika give away?
| |
Grey |
Purple |
Total |
Total |
Before
|
2x1 =
2 u |
7x1 =
7 u |
9x1 =
9 u |
3x3 =
9 u |
Change
|
- 0.4x1 =
- 0.4 u |
- 196 |
|
- 2x3 =
- 6 u |
After
|
1.6x1 =
1.6 u |
7 u - 196 |
|
1x3 =
3 u |
The total number of coins that Erika had at first is repeated. Make the total number of coins at first the same. LCM 9 and 3 is 9.
Number of grey coins that Erika gave away
= 20% x 2 u
=
20100 x 2 u
= 0.4 u
0.4 u - 196 = 6 u
6 u - 0.4 u = 196
5.6 u = 196
1 u = 196 ÷ 5.6 = 35
Number of coins that Erika gave away
= 6 u
= 6 x 35
= 210
Answer(s): 210
