请教over的意思.

after paying a 10 percent tax on all income over $3,000, a person had a net income of 12000.what was the income before tax.

over 是指凡超过3000的收入都要交10%的税

还是指超过3000的部分要交10%的税?

我觉得问题不是over，是在income上面！