A, B, C, and D have a total of 190 yuan. If A increases 10 yuan, B spends 20 yuan, C doubles his money, and D's money decreases by half, then the money of the four people here is equal. How much money did A have?
甲、乙、丙、丁四人共有190元钱，如果甲增加10元，乙用去20元，丙的钱增加一倍，丁的钱减少一半，那么四个人此地的钱就相等．甲原来有多少元钱．
<gadget id="calculator">190 - 20</gadget>
<output>170</output>

<gadget id="calculator">10 + 170</gadget>
<output>180</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 + 1 + (1/2) + 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">180 / (9/2)</gadget>
<output>40</output>

<gadget id="calculator">40 - 10</gadget>
<output>30</output>

<result>30</result>