Three girls, Min, Xuan and Xylia had a total of 3480 marbles. Some exchanges were made. First, Min gave Xuan as many marbles as Xuan had. After that, Xuan gave
13 of whatever she had then to Xylia. Finally, Xylia gave
15 of whatever she had to Min. As a result, they each had the same number of marbles. How many marbles did Min have at first?
|
Min |
Xuan |
Xylia |
Total |
Before 1 |
? |
1 u |
|
3480 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
3 p |
|
3480 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
2 p |
|
|
Before 3 |
|
|
5 boxes |
3480 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
3480 |
3 groups = 3480
1 group = 3480 ÷ 3 = 1160
1 group = 4 boxes 4 boxes = 1160
1 box = 1160 ÷ 4 = 290
2 p = 1 group
1 p = 1160 ÷ 2 = 580
3 p = 3 x 580 = 1740
3 p = 2 u
2 u = 1740
1 u = 1740 ÷ 2 = 870
Number of marbles that Min had at first
= 1 group - 1 box + 1 u
= 1160 - 290 + 870
= 1740
Answer(s): 1740