Three girls, Pamela, Cathy and Barbara had a total of 1920 stickers. Some exchanges were made. First, Pamela gave Cathy as many stickers as Cathy had. After that, Cathy gave
13 of whatever she had then to Barbara. Finally, Barbara gave
15 of whatever she had to Pamela. As a result, they each had the same number of stickers. How many stickers did Pamela have at first?
|
Pamela |
Cathy |
Barbara |
Total |
Before 1 |
? |
1 u |
|
1920 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
3 p |
|
1920 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
2 p |
|
|
Before 3 |
|
|
5 boxes |
1920 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
1920 |
3 groups = 1920
1 group = 1920 ÷ 3 = 640
1 group = 4 boxes 4 boxes = 640
1 box = 640 ÷ 4 = 160
2 p = 1 group
1 p = 640 ÷ 2 = 320
3 p = 3 x 320 = 960
3 p = 2 u
2 u = 960
1 u = 960 ÷ 2 = 480
Number of stickers that Pamela had at first
= 1 group - 1 box + 1 u
= 640 - 160 + 480
= 960
Answer(s): 960