Three girls, Dana, Joelle and Wendy had a total of 3840 stamps. Some exchanges were made. First, Dana gave Joelle as many stamps as Joelle had. After that, Joelle gave
15 of whatever she had then to Wendy. Finally, Wendy gave
13 of whatever she had to Dana. As a result, they each had the same number of stamps. How many stamps did Dana have at first?
|
Dana |
Joelle |
Wendy |
Total |
Before 1 |
? |
1 u |
|
3840 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
3840 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
3 boxes |
3840 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
2 boxes |
|
After 3 |
1 group |
1 group |
1 group |
3840 |
3 groups = 3840
1 group = 3840 ÷ 3 = 1280
1 group = 2 boxes 2 boxes = 1280
1 box = 1280 ÷ 2 = 640
4 p = 1 group
1 p = 1280 ÷ 4 = 320
5 p = 5 x 320 = 1600
5 p = 2 u
2 u = 1600
1 u = 1600 ÷ 2 = 800
Number of stamps that Dana had at first
= 1 group - 1 box + 1 u
= 1280 - 640 + 800
= 1440
Answer(s): 1440