Sarah bought some buttons. She gave
14 of the buttons to her brother and sold
35 of the remaining buttons. After that, she bought another 42 buttons and had the same number of buttons that she bought at first. How many buttons did Sarah buy at first?
| Her brother |
Remaining buttons |
Bought buttons |
Total |
1x5 =
5 u |
3x5 =
15 u |
|
4x5 =
20 u |
| |
Sold |
Left |
|
|
| |
3x3 |
2x3 |
|
|
| 5 u |
9 u |
6 u |
42 |
|
The remaining number of buttons before Sarah bought another 42 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 Sarah had left and bought after that = 6 u + 42
20 u = 6 u + 42
20 u - 6 u = 42
14 u = 42
1 u = 42 ÷ 14 = 3
Total number of buttons at first
= 20 u
= 20 x 3
= 60
Answer(s): 60
