Three girls, Shiyun, Barbara and Xandra had a total of 660 coins. Some exchanges were made. First, Shiyun gave Barbara as many coins as Barbara had. After that, Barbara gave
13 of whatever she had then to Xandra. Finally, Xandra gave
15 of whatever she had to Shiyun. As a result, they each had the same number of coins. How many coins did Shiyun have at first?
|
Shiyun |
Barbara |
Xandra |
Total |
Before 1 |
? |
1 u |
|
660 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
3 p |
|
660 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
2 p |
|
|
Before 3 |
|
|
5 boxes |
660 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
660 |
3 groups = 660
1 group = 660 ÷ 3 = 220
1 group = 4 boxes 4 boxes = 220
1 box = 220 ÷ 4 = 55
2 p = 1 group
1 p = 220 ÷ 2 = 110
3 p = 3 x 110 = 330
3 p = 2 u
2 u = 330
1 u = 330 ÷ 2 = 165
Number of coins that Shiyun had at first
= 1 group - 1 box + 1 u
= 220 - 55 + 165
= 330
Answer(s): 330