Three girls, Shannon, Eva and Pamela had a total of 1200 erasers. Some exchanges were made. First, Shannon gave Eva as many erasers as Eva had. After that, Eva gave
15 of whatever she had then to Pamela. Finally, Pamela gave
15 of whatever she had to Shannon. As a result, they each had the same number of erasers. How many erasers did Shannon have at first?
|
Shannon |
Eva |
Pamela |
Total |
Before 1 |
? |
1 u |
|
1200 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
1200 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
5 boxes |
1200 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
1200 |
3 groups = 1200
1 group = 1200 ÷ 3 = 400
1 group = 4 boxes 4 boxes = 400
1 box = 400 ÷ 4 = 100
4 p = 1 group
1 p = 400 ÷ 4 = 100
5 p = 5 x 100 = 500
5 p = 2 u
2 u = 500
1 u = 500 ÷ 2 = 250
Number of erasers that Shannon had at first
= 1 group - 1 box + 1 u
= 400 - 100 + 250
= 550
Answer(s): 550