Three girls, Gabby, Anna and Gem had a total of 3600 marbles. Some exchanges were made. First, Gabby gave Anna as many marbles as Anna had. After that, Anna gave
14 of whatever she had then to Gem. Finally, Gem gave
15 of whatever she had to Gabby. As a result, they each had the same number of marbles. How many marbles did Gabby have at first?
|
Gabby |
Anna |
Gem |
Total |
Before 1 |
? |
1 u |
|
3600 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
4 p |
|
3600 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
3 p |
|
|
Before 3 |
|
|
5 boxes |
3600 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
4 boxes |
|
After 3 |
1 group |
1 group |
1 group |
3600 |
3 groups = 3600
1 group = 3600 ÷ 3 = 1200
1 group = 4 boxes 4 boxes = 1200
1 box = 1200 ÷ 4 = 300
3 p = 1 group
1 p = 1200 ÷ 3 = 400
4 p = 4 x 400 = 1600
4 p = 2 u
2 u = 1600
1 u = 1600 ÷ 2 = 800
Number of marbles that Gabby had at first
= 1 group - 1 box + 1 u
= 1200 - 300 + 800
= 1700
Answer(s): 1700