Three girls, Jen, Yoko and Shannon had a total of 1320 marbles. Some exchanges were made. First, Jen gave Yoko as many marbles as Yoko had. After that, Yoko gave
15 of whatever she had then to Shannon. Finally, Shannon gave
13 of whatever she had to Jen. As a result, they each had the same number of marbles. How many marbles did Jen have at first?
|
Jen |
Yoko |
Shannon |
Total |
Before 1 |
? |
1 u |
|
1320 |
Change 1 |
- 1 u |
+ 1 u |
|
|
After 1 |
|
2 u |
|
|
Before 2 |
|
5 p |
|
1320 |
Change 2 |
|
- 1 p |
+ 1 p |
|
After 2 |
|
4 p |
|
|
Before 3 |
|
|
3 boxes |
1320 |
Change 3 |
+ 1 box |
|
- 1 box |
|
After 3 |
|
|
2 boxes |
|
After 3 |
1 group |
1 group |
1 group |
1320 |
3 groups = 1320
1 group = 1320 ÷ 3 = 440
1 group = 2 boxes 2 boxes = 440
1 box = 440 ÷ 2 = 220
4 p = 1 group
1 p = 440 ÷ 4 = 110
5 p = 5 x 110 = 550
5 p = 2 u
2 u = 550
1 u = 550 ÷ 2 = 275
Number of marbles that Jen had at first
= 1 group - 1 box + 1 u
= 440 - 220 + 275
= 495
Answer(s): 495