Tiffany had 120 more buttons than Sarah. After Tiffany gave away
25 of her buttons and Sarah gave away
23 of her buttons, Sarah had 100 less buttons than Tiffany. How many buttons did Tiffany have at first?
| |
Tiffany |
Sarah |
Comparing Tiffany and
Sarah at first |
120 more |
|
| Before |
5x3 |
+ 120 |
3x5 |
| Change |
- 2x3 |
- 48 |
- 2x5 |
| After |
3x3 |
+ 72 |
1x5 |
Comparing Tiffany and
Sarah in the end |
|
100 less |
| |
Tiffany |
Sarah |
| Before |
15 u + 120 |
15 u |
| Change |
- 6 u - 48 |
- 10 u |
| After |
9 u + 72 |
5 u |
25 x 120 = 48
120 - 48 = 72
Sarah had 100 less buttons than Tiffany in the end. So, if Sarah had another 100 buttons in the end, the number of buttons that Sarah and Tiffany each had would be the same.
9 u + 72 = 5 u + 100
9 u - 5 u = 100 - 72
4 u = 28
1 u = 28 ÷ 4 = 7
Number of buttons that Tiffany had at first
= 15 u + 120
= 15 x 7 + 120
= 105 + 120
= 225
Answer(s): 225
