Wendy had some coin collection.
13 of them were white and the rest were gold. She gave away 145 of the gold coins and 50% of the white coins. She then had
17 of her coin collection left. How many coins did Wendy give away?
| |
White |
Gold |
Total |
Total |
Before
|
1x7 =
7 u |
2x7 =
14 u |
3x7 =
21 u |
7x3 =
21 u |
Change
|
- 0.5x7 =
- 3.5 u |
- 145 |
|
- 6x3 =
- 18 u |
After
|
0.5x7 =
3.5 u |
14 u - 145 |
|
1x3 =
3 u |
The total number of coins that Wendy had at first is repeated. Make the total number of coins at first the same. LCM 3 and 7 is 21.
Number of white coins that Wendy gave away
= 50% x 1 u
=
50100 x 1 u
= 0.5 u
3.5 u - 145 = 18 u
18 u - 3.5 u = 145
14.5 u = 145
1 u = 145 ÷ 14.5 = 10
Number of coins that Wendy gave away
= 18 u
= 18 x 10
= 180
Answer(s): 180
