Mary had 69 more buttons than Min. After Mary gave away
13 of her buttons and Min gave away
35 of her buttons, Min had 62 less buttons than Mary. How many buttons did Mary have at first?
| |
Mary |
Min |
Comparing Mary and
Min at first |
69 more |
|
| Before |
3x5 |
+ 69 |
5x3 |
| Change |
- 1x5 |
- 23 |
- 3x3 |
| After |
2x5 |
+ 46 |
2x3 |
Comparing Mary and
Min in the end |
|
62 less |
| |
Mary |
Min |
| Before |
15 u + 69 |
15 u |
| Change |
- 5 u - 23 |
- 9 u |
| After |
10 u + 46 |
6 u |
13 x 69 = 23
69 - 23 = 46
Min had 62 less buttons than Mary in the end. So, if Min had another 62 buttons in the end, the number of buttons that Min and Mary each had would be the same.
10 u + 46 = 6 u + 62
10 u - 6 u = 62 - 46
4 u = 16
1 u = 16 ÷ 4 = 4
Number of buttons that Mary had at first
= 15 u + 69
= 15 x 4 + 69
= 60 + 69
= 129
Answer(s): 129
