Glen, Ian and Michael had the same number of balls. Michael gave 0.5 of his balls to Ian. Then Ian gave 0.25 of his balls to Glen. Finally, after Ian gave 25 balls to Michael, he had the same number of balls as Michael. How many balls did Michael have at first?
| |
Glen |
Ian |
Michael |
| 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 |
|
- 25 |
+ 25 |
| After 3 |
1.375 u |
1.125 u - 25 |
0.5 u + 25 |
Number of balls that Ian gave to Glen
= 0.25 x 1.5 u
= 0.375 u
The number of balls that Ian and Michael had in the end is the same.
1.125 u - 25 = 0.5 u + 25
1.125 u - 0.5 u = 25 + 25
0.625 u = 50
1 u = 50 ÷ 0.625 = 80
Number of balls that Michael had at first
= 1 u
= 80
Answer(s): 80
