Shannon bought some coins. She gave
13 of the coins to her cousin and sold
35 of the remaining coins. After that, she bought another 99 coins and had the same number of coins that she bought at first. How many coins did Shannon buy at first?
| Her cousin |
Remaining coins |
Bought coins |
Total |
1x5 =
5 u |
2x5 =
10 u |
|
3x5 =
15 u |
| |
Sold |
Left |
|
|
| |
3x2 |
2x2 |
|
|
| 5 u |
6 u |
4 u |
99 |
|
The remaining number of coins before Shannon bought another 99 coins is repeated. Make the remaining number of coins the same. LCM of 2 and 5 is 10.
Total number of coins at first = 15 u
Number of coins that Shannon had left and bought after that = 4 u + 99
15 u = 4 u + 99
15 u - 4 u = 99
11 u = 99
1 u = 99 ÷ 11 = 9
Total number of coins at first
= 15 u
= 15 x 9
= 135
Answer(s): 135
