Tom had 3 times as many purple staplers as green staplers. After giving away 6 purple staplers and buying another 4 green staplers, he had an equal number of purple and green staplers. How many purple staplers did Tom have at first?
| |
Purple staplers |
Green staplers |
| Before |
3 u |
1 u |
| Change |
- 6 |
+ 4 |
| After |
3 u - 6 |
1 u + 4 |
The number of purple and green staplers is the same in the end.
3 u - 6 = 1 u + 4
3 u - 1 u = 4 + 6
2 u = 6 + 4
2 u = 10
1 u = 10 ÷ 2 = 5
Number of purple staplers that Tom had at first
= 3 u
= 3 x 5
= 15
Answer(s): 15
