Julie, Erika and Jade each had some balls and decided to play a game with their balls. In round 1, Julie lost
13 of her balls to Erika. In round 2, Erika lost
13 of her total number of balls to Jade. In round 3, Jade lost
13 of her total number of balls to Julie. In the end, Julie, Erika and Jade had 121, 92 and 66 balls respectively. How many balls did Erika have at first?
|
Julie |
Erika |
Jade |
|
|
94 |
|
Before 1 |
3 b |
|
|
Change 1 |
- 1 b |
+ 1 b |
|
After 1 |
2 b |
138 |
|
Before 2 |
88 |
3 u |
|
Change 2 |
|
- 1 u |
+ 1 u |
After 2 |
|
2 u |
99 |
Before 3 |
|
|
3 p |
Change 3 |
+ 1 p |
|
- 1 p |
After 3 |
|
|
2 p |
Comparing Julie, Erika and Jade in the end |
121 |
92 |
66 |
Working backwards.
2 p = 66
1 p = 66 ÷ 2 = 33
At the start of Round 3:
Number of balls that Jade had
= 3 p
= 3 x 33
= 99
2 u = 92
1 u = 92 ÷ 2 = 46
At the start of Round 2:
Number of balls that Erika had
= 3 u
= 3 x 46
= 138
At the start of Round 2:
Number of balls that Julie had
= 121 - 33
= 88
2 b = 88
1 b = 88 ÷ 2 = 44
At the start of Round 1:
Number of balls that Erika had
= 138 - 1 b
= 138 - 44
= 94
Answer(s): 94