Three girls, Ivory, Joelle and Emma had a total of 1680 erasers. Some exchanges were made. First, Ivory gave Joelle as many erasers as Joelle had. After that, Joelle gave
15 of whatever she had then to Emma. Finally, Emma gave
13 of whatever she had to Ivory. As a result, they each had the same number of erasers. How many erasers did Ivory have at first?
|
Ivory |
Joelle |
Emma |
Total |
Before 1 |
? |
1 u |
|
1680 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
1680 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
3 boxes |
1680 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
2 boxes |
|
After 3 |
1 group |
1 group |
1 group |
1680 |
3 groups = 1680
1 group = 1680 ÷ 3 = 560
1 group = 2 boxes 2 boxes = 560
1 box = 560 ÷ 2 = 280
4 p = 1 group
1 p = 560 ÷ 4 = 140
5 p = 5 x 140 = 700
5 p = 2 u
2 u = 700
1 u = 700 ÷ 2 = 350
Number of erasers that Ivory had at first
= 1 group - 1 box + 1 u
= 560 - 280 + 350
= 630
Answer(s): 630