Xuan had 90 more buttons than Kimberly. After Xuan gave away
25 of her buttons and Kimberly gave away
23 of her buttons, Kimberly had 78 less buttons than Xuan. How many buttons did Xuan have at first?
| |
Xuan |
Kimberly |
Comparing Xuan and
Kimberly at first |
90 more |
|
| Before |
5x3 |
+ 90 |
3x5 |
| Change |
- 2x3 |
- 36 |
- 2x5 |
| After |
3x3 |
+ 54 |
1x5 |
Comparing Xuan and
Kimberly in the end |
|
78 less |
| |
Xuan |
Kimberly |
| Before |
15 u + 90 |
15 u |
| Change |
- 6 u - 36 |
- 10 u |
| After |
9 u + 54 |
5 u |
25 x 90 = 36
90 - 36 = 54
Kimberly had 78 less buttons than Xuan in the end. So, if Kimberly had another 78 buttons in the end, the number of buttons that Kimberly and Xuan each had would be the same.
9 u + 54 = 5 u + 78
9 u - 5 u = 78 - 54
4 u = 24
1 u = 24 ÷ 4 = 6
Number of buttons that Xuan had at first
= 15 u + 90
= 15 x 6 + 90
= 90 + 90
= 180
Answer(s): 180
