Zoe bought some erasers. She gave
17 of the erasers to her sister and sold
25 of the remaining erasers. After that, she bought another 68 erasers and had the same number of erasers that she bought at first. How many erasers did Zoe buy at first?
| Her sister |
Remaining erasers |
Bought erasers |
Total |
1x5 =
5 u |
6x5 =
30 u |
|
7x5 =
35 u |
| |
Sold |
Left |
|
|
| |
2x6 |
3x6 |
|
|
| 5 u |
12 u |
18 u |
68 |
|
The remaining number of erasers before Zoe bought another 68 erasers is repeated. Make the remaining number of erasers the same. LCM of 6 and 5 is 30.
Total number of erasers at first = 35 u
Number of erasers that Zoe had left and bought after that = 18 u + 68
35 u = 18 u + 68
35 u - 18 u = 68
17 u = 68
1 u = 68 ÷ 17 = 4
Total number of erasers at first
= 35 u
= 35 x 4
= 140
Answer(s): 140
