Dad keeps 40% of this month's salary as education investment, and deposits the other 720 yuan bonus and the remaining salary in the bank. The money deposited in the bank is exactly what Dad's original salary was (6/7). How much is Dad's salary this month?
爸爸把本月工资的40%作为教育投资留下来，把另外的720元奖金和剩余工资合在一起存入银行，存入银行的钱正好是爸爸原来工资的(6/7)．爸爸本月工资多少元？
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(6/7) - (3/5)</gadget>
<output>9/35 = around 0.257143</output>

<gadget id="calculator">720 / (9/35)</gadget>
<output>2_800</output>

<result>2_800</result>