Zoe had 120 more buttons than Irene. After Zoe gave away
15 of her buttons and Irene gave away
23 of her buttons, Irene had 180 less buttons than Zoe. How many buttons did Zoe have at first?
| |
Zoe |
Irene |
Comparing Zoe and
Irene at first |
120 more |
|
| Before |
5x3 |
+ 120 |
3x5 |
| Change |
- 1x3 |
- 24 |
- 2x5 |
| After |
4x3 |
+ 96 |
1x5 |
Comparing Zoe and
Irene in the end |
|
180 less |
| |
Zoe |
Irene |
| Before |
15 u + 120 |
15 u |
| Change |
- 3 u - 24 |
- 10 u |
| After |
12 u + 96 |
5 u |
15 x 120 = 24
120 - 24 = 96
Irene had 180 less buttons than Zoe in the end. So, if Irene had another 180 buttons in the end, the number of buttons that Irene and Zoe each had would be the same.
12 u + 96 = 5 u + 180
12 u - 5 u = 180 - 96
7 u = 84
1 u = 84 ÷ 7 = 12
Number of buttons that Zoe had at first
= 15 u + 120
= 15 x 12 + 120
= 180 + 120
= 300
Answer(s): 300
