Riordan and David had 90 mochi balls each. Riordan gave 20% of his mochi balls to David. After receiving the mochi balls from Riordan, David gave 50% of his total mochi balls to Xuan. How many mochi balls had David left?
| |
Riordan |
David |
Xuan |
| Before |
100% |
100% |
|
| Change 1 |
- 20% |
+ 20% |
|
| After 1 |
80% |
120% |
|
| Change 2 |
|
- 60% |
+ 60% |
| After 2 |
|
60% |
|
Percentage of mochi balls after David received from Riordan
= 100% + 20%
= 120%
Percentage of David's mochi balls that Xuan had after receiving from David
= 50% x 120%
=
50100 x 120%
= 60%
Percentage of mochi balls that David had left after giving to Xuan
= 120% - 60%
= 60%
100% = 90
Number of mochi balls that David had left
= 60% x 90
=
60100 x 90
= 54
Answer(s): 54
