Peter had 4 times as many brown files as red files. After giving away 6 brown files and buying another 30 red files, he had an equal number of brown and red files. How many brown files did Peter have at first?
| |
Brown files |
Red files |
| Before |
4 u |
1 u |
| Change |
- 6 |
+ 30 |
| After |
4 u - 6 |
1 u + 30 |
The number of brown and red files is the same in the end.
4 u - 6 = 1 u + 30
4 u - 1 u = 30 + 6
3 u = 6 + 30
3 u = 36
1 u = 36 ÷ 3 = 12
Number of brown files that Peter had at first
= 4 u
= 4 x 12
= 48
Answer(s): 48
