The result of adding the minuend, the subtrahend and the difference is 240, and the subtrahend is 3 times the difference. What is the subtrahend?
被减数、减数与差相加的结果是240，其中减数是差的3倍，求减数是多少？
<gadget id="calculator">240 / 2</gadget>
<output>120</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">120 * (3/4)</gadget>
<output>90</output>

<result>90</result>