Billy had 3 times as many brown files as green files. After giving away 5 brown files and buying another 3 green files, he had an equal number of brown and green files. How many brown files did Billy have at first?
| |
Brown files |
Green files |
| Before |
3 u |
1 u |
| Change |
- 5 |
+ 3 |
| After |
3 u - 5 |
1 u + 3 |
The number of brown and green files is the same in the end.
3 u - 5 = 1 u + 3
3 u - 1 u = 3 + 5
2 u = 5 + 3
2 u = 8
1 u = 8 ÷ 2 = 4
Number of brown files that Billy had at first
= 3 u
= 3 x 4
= 12
Answer(s): 12
