A person is paid 300 yuan and 3 carpets for a month of work. After working for 13 days, he quits and gets 49 yuan and 4 carpets. How much is each carpet (30 days in this month)?
某人工作一个月的报酬是300元和3条地毯，他干13天后，有事不干了，得到49元和4条地毯，则每条地毯是多少元(此月30天)？
<gadget id="calculator">13 / 30</gadget>
<output>13/30 = around 0.433333</output>

<gadget id="calculator">300 * (13/30)</gadget>
<output>130</output>

<gadget id="calculator">130 - 49</gadget>
<output>81</output>

<gadget id="calculator">3 * (13/30)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">4 - (13/10)</gadget>
<output>27/10 = around 2.7</output>

<gadget id="calculator">81 / (27/10)</gadget>
<output>30</output>

<result>30</result>