Sarah had 90 more buttons than Anna. After Sarah gave away
13 of her buttons and Anna gave away
35 of her buttons, Anna had 88 less buttons than Sarah. How many buttons did Sarah have at first?
| |
Sarah |
Anna |
Comparing Sarah and
Anna at first |
90 more |
|
| Before |
3x5 |
+ 90 |
5x3 |
| Change |
- 1x5 |
- 30 |
- 3x3 |
| After |
2x5 |
+ 60 |
2x3 |
Comparing Sarah and
Anna in the end |
|
88 less |
| |
Sarah |
Anna |
| Before |
15 u + 90 |
15 u |
| Change |
- 5 u - 30 |
- 9 u |
| After |
10 u + 60 |
6 u |
13 x 90 = 30
90 - 30 = 60
Anna had 88 less buttons than Sarah in the end. So, if Anna had another 88 buttons in the end, the number of buttons that Anna and Sarah each had would be the same.
10 u + 60 = 6 u + 88
10 u - 6 u = 88 - 60
4 u = 28
1 u = 28 ÷ 4 = 7
Number of buttons that Sarah had at first
= 15 u + 90
= 15 x 7 + 90
= 105 + 90
= 195
Answer(s): 195
