Lucy had the same number of white, black and silver buttons at first. After giving some white and black buttons and 49 silver buttons away, Lucy had 172 buttons left. There were 2 times as many white buttons as black buttons left. The number of silver buttons left was 28 fewer than the number of white buttons left. How many silver buttons did she have at first?
| |
Black |
White |
Silver |
Total |
| Before |
2 u + 21 |
2 u + 21 |
2 u + 21 |
|
| Change |
- 1 u - 21 |
- 21 |
- 49 |
|
| After |
1 u |
2 u |
2 u - 28 |
172 |
Lucy had the same number of white, black and silver buttons at first.
Total number of buttons in the end
= 1 u + 2 u + 2 u - 28
= 5 u - 28
5 u - 28 = 172
5 u = 172 + 28
5 u = 200
1 u = 200 ÷ 5 = 40
Number of silver buttons that Lucy had at first
= 2 u - 28 + 49
= 2 u + 21
= 2 x 40 + 21
= 101
Answer(s): 101
