Xavier, Ahmad and Paul had the same number of balls. Paul gave 0.5 of his balls to Ahmad. Then Ahmad gave 0.25 of his balls to Xavier. Finally, after Ahmad gave 20 balls to Paul, he had the same number of balls as Paul. How many balls did Paul have at first?
| |
Xavier |
Ahmad |
Paul |
| Before |
1 u |
1 u |
1 u |
| Change 1 |
|
+ 0.5 u |
- 0.5 u |
| After 1 |
1 u |
1.5 u |
0.5 u |
| Change 2 |
+ 0.375 u |
- 0.375 u |
|
| After 2 |
1.375 u |
1.125 u |
0.5 u |
| Change 3 |
|
- 20 |
+ 20 |
| After 3 |
1.375 u |
1.125 u - 20 |
0.5 u + 20 |
Number of balls that Ahmad gave to Xavier
= 0.25 x 1.5 u
= 0.375 u
The number of balls that Ahmad and Paul had in the end is the same.
1.125 u - 20 = 0.5 u + 20
1.125 u - 0.5 u = 20 + 20
0.625 u = 40
1 u = 40 ÷ 0.625 = 64
Number of balls that Paul had at first
= 1 u
= 64
Answer(s): 64
