Fabian had 3 times as many white notebooks as purple notebooks. After giving away 6 white notebooks and buying another 6 purple notebooks, he had an equal number of white and purple notebooks. How many white notebooks did Fabian have at first?
| |
White notebooks |
Purple notebooks |
| Before |
3 u |
1 u |
| Change |
- 6 |
+ 6 |
| After |
3 u - 6 |
1 u + 6 |
The number of white and purple notebooks is the same in the end.
3 u - 6 = 1 u + 6
3 u - 1 u = 6 + 6
2 u = 6 + 6
2 u = 12
1 u = 12 ÷ 2 = 6
Number of white notebooks that Fabian had at first
= 3 u
= 3 x 6
= 18
Answer(s): 18
