Lucy, Shiyun and Natalie each had some balls and decided to play a game with their balls. In round 1, Lucy lost
12 of her balls to Shiyun. In round 2, Shiyun lost
12 of her total number of balls to Natalie. In round 3, Natalie lost
12 of her total number of balls to Lucy. In the end, Lucy, Shiyun and Natalie had 125, 90 and 59 balls respectively. How many balls did Shiyun have at first?
|
Lucy |
Shiyun |
Natalie |
Before 1 |
2 b |
114 |
|
Change 1 |
- 1 b |
+ 1 b |
|
After 1 |
1 b |
180 |
|
Before 2 |
66 |
2 u |
|
Change 2 |
|
- 1 u |
+1 |
After 2 |
|
1 u |
118 |
Before 3 |
|
|
2 p |
Change 3 |
+ 1 p |
|
- 1 p |
After 3 |
|
|
1 p |
Comparing Lucy, Shiyun and Natalie in the end |
125 |
90 |
59 |
Working backwards.
1 p = 59
At the start of Round 3:
Number of balls that Natalie had
= 2 p
= 2 x 59
= 118
At the start of Round 2:
Number of balls that Lucy had
= 125 - 1 p
= 125 - 59
= 66
At the end of Round 3:
Number of balls that Shiyun had = 90
1 u = 90
At the end of Round 1:
Number of balls that Shiyun had
= 2 u
= 2 x 90
= 180
1 b = 66
At the end of Round 1:
Number of balls that Lucy had = 66
At the start of Round 1:
Number of balls that Shiyun had
= 180 - 1 b
= 180 - 66
= 114
Answer(s): 114