Erika bought some buttons. She gave
14 of the buttons to her sister and sold
25 of the remaining buttons. After that, she bought another 55 buttons and had the same number of buttons that she bought at first. How many buttons did Erika buy at first?
| Her sister |
Remaining buttons |
Bought buttons |
Total |
1x5 =
5 u |
3x5 =
15 u |
|
4x5 =
20 u |
| |
Sold |
Left |
|
|
| |
2x3 |
3x3 |
|
|
| 5 u |
6 u |
9 u |
55 |
|
The remaining number of buttons before Erika bought another 55 buttons is repeated. Make the remaining number of buttons the same. LCM of 3 and 5 is 15.
Total number of buttons at first = 20 u
Number of buttons that Erika had left and bought after that = 9 u + 55
20 u = 9 u + 55
20 u - 9 u = 55
11 u = 55
1 u = 55 ÷ 11 = 5
Total number of buttons at first
= 20 u
= 20 x 5
= 100
Answer(s): 100
