Xiaomin and Xiaogang are both stamp collectors. Now the ratio of the number of stamps of Xiaomin and Xiaogang is 3:4. If Xiaogang gives Xiaomin nine stamps, then the number of stamps of the two of them is equal. How many stamps do they have in total?

Xiaomin and Xiaogang are both stamp collectors. Now the ratio of the number of stamps of Xiaomin and Xiaogang is 3:4. If Xiaogang gives Xiaomin nine stamps, then the number of stamps of the two of them is equal. How many stamps do they have in total?

The total number of stamps for the two remained unchanged
Xiaomin originally accounted for 3 / 7 of the total
Xiaomin now accounts for 1 / 2 of the total
The total number is: 9 (1 / 2-3 / 7) = 126