Three girls, Eva, Barbara and Yen had a total of 3960 marbles. Some exchanges were made. First, Eva gave Barbara as many marbles as Barbara had. After that, Barbara gave
15 of whatever she had then to Yen. Finally, Yen gave
14 of whatever she had to Eva. As a result, they each had the same number of marbles. How many marbles did Eva have at first?
|
Eva |
Barbara |
Yen |
Total |
Before 1 |
? |
1 u |
|
3960 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
3960 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
4 boxes |
3960 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
3 boxes |
|
After 3 |
1 group |
1 group |
1 group |
3960 |
3 groups = 3960
1 group = 3960 ÷ 3 = 1320
1 group = 3 boxes 3 boxes = 1320
1 box = 1320 ÷ 3 = 440
4 p = 1 group
1 p = 1320 ÷ 4 = 330
5 p = 5 x 330 = 1650
5 p = 2 u
2 u = 1650
1 u = 1650 ÷ 2 = 825
Number of marbles that Eva had at first
= 1 group - 1 box + 1 u
= 1320 - 440 + 825
= 1705
Answer(s): 1705