Three girls, Yen, Jean and Tammy had a total of 1200 coins. Some exchanges were made. First, Yen gave Jean as many coins as Jean had. After that, Jean gave
15 of whatever she had then to Tammy. Finally, Tammy gave
15 of whatever she had to Yen. As a result, they each had the same number of coins. How many coins did Yen have at first?
|
Yen |
Jean |
Tammy |
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 coins that Yen had at first
= 1 group - 1 box + 1 u
= 400 - 100 + 250
= 550
Answer(s): 550