Lynn bought some stamps. She gave
13 of the stamps to her cousin and sold
25 of the remaining stamps. After that, she bought another 18 stamps and had the same number of stamps that she bought at first. How many stamps did Lynn buy at first?
| Her cousin |
Remaining stamps |
Bought stamps |
Total |
1x5 =
5 u |
2x5 =
10 u |
|
3x5 =
15 u |
| |
Sold |
Left |
|
|
| |
2x2 |
3x2 |
|
|
| 5 u |
4 u |
6 u |
18 |
|
The remaining number of stamps before Lynn bought another 18 stamps is repeated. Make the remaining number of stamps the same. LCM of 2 and 5 is 10.
Total number of stamps at first = 15 u
Number of stamps that Lynn had left and bought after that = 6 u + 18
15 u = 6 u + 18
15 u - 6 u = 18
9 u = 18
1 u = 18 ÷ 9 = 2
Total number of stamps at first
= 15 u
= 15 x 2
= 30
Answer(s): 30
