For a fraction, the sum of the numerator and the denominator is 48. If 1 is added to both the numerator and the denominator, the resulting fraction will be divided into (1/4). What is the original fraction?
一个分数，分子与分母的和是48，如果分子、分母都加上1，所得分数约分后为(1/4)，原来的分数是多少．
<gadget id="calculator">48 + 1 + 1</gadget>
<output>50</output>

<gadget id="calculator">1 + 4</gadget>
<output>5</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 * (1/5)</gadget>
<output>10</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">40 - 1</gadget>
<output>39</output>

<gadget id="calculator">9 / 39</gadget>
<output>3/13 = around 0.230769</output>

<result>3/13 = around 0.230769</result>