Tammy, Usha and Anna each had some balls and decided to play a game with their balls. In round 1, Tammy lost
12 of her balls to Usha. In round 2, Usha lost
12 of her total number of balls to Anna. In round 3, Anna lost
12 of her total number of balls to Tammy. In the end, Tammy, Usha and Anna had 115, 96 and 72 balls respectively. How many balls did Usha have at first?
|
Tammy |
Usha |
Anna |
Before 1 |
2 b |
149 |
|
Change 1 |
- 1 b |
+ 1 b |
|
After 1 |
1 b |
192 |
|
Before 2 |
43 |
2 u |
|
Change 2 |
|
- 1 u |
+1 |
After 2 |
|
1 u |
144 |
Before 3 |
|
|
2 p |
Change 3 |
+ 1 p |
|
- 1 p |
After 3 |
|
|
1 p |
Comparing Tammy, Usha and Anna in the end |
115 |
96 |
72 |
Working backwards.
1 p = 72
At the start of Round 3:
Number of balls that Anna had
= 2 p
= 2 x 72
= 144
At the start of Round 2:
Number of balls that Tammy had
= 115 - 1 p
= 115 - 72
= 43
At the end of Round 3:
Number of balls that Usha had = 96
1 u = 96
At the end of Round 1:
Number of balls that Usha had
= 2 u
= 2 x 96
= 192
1 b = 43
At the end of Round 1:
Number of balls that Tammy had = 43
At the start of Round 1:
Number of balls that Usha had
= 192 - 1 b
= 192 - 43
= 149
Answer(s): 149