The charging standard for local calls in a certain city is as follows: 0.20 yuan for call time within 3 minutes (including 3 minutes), and 0.10 yuan for each additional minute of call time longer than 3 minutes (less than 1 minute is also counted as 1 minute). It costs 1.2 yuan to make a local call, and how many minutes is the longest call this time.
某市的市内电话收费标准如下：通话时间，3分钟以内(含3分钟)收费0.20元，通话时间3分钟以上，每增加1分钟(不满1分钟也算作1分钟)，收0.10元．打一次市内电话付费1.2元，这次电话最长打了多少分钟分钟．
<gadget id="calculator">1.2 - 0.2</gadget>
<output>1</output>

<gadget id="calculator">1 / 0.1</gadget>
<output>10</output>

<gadget id="calculator">10 + 3</gadget>
<output>13</output>

<result>13</result>