David and Cathy had the same number of mochi balls. After Cathy gave away 20 mochi balls and David gave away 37 mochi balls, Cathy had 2 times as many mochi balls as David. How many mochi balls did each of them have at first?
| |
David |
Cathy |
| Before |
1 u + 37 |
2 u + 20 |
| Change |
- 37 |
- 20 |
| After |
1 u |
2 u |
The number of mochi balls that David and Cathy had at first is the same.
2 u + 20 = 1 u + 37
2 u - 1 u = 37 - 20
1 u = 17
1 u = 17 ÷ 1 = 17
Number of mochi balls that each of them had at first
= 1 u + 37
= 17 + 37
= 54
Answer(s): 54
