Tiantian called her mother and spent 1.2 yuan. The telecommunications bureau stipulates that the first 3 minutes of local calls are 0.2 yuan, and 0.1 yuan per minute thereafter. How long did Tiantian talk to his mother?
田田给妈妈打了一个电话，花了1.2元钱．电信局规定：市内电话前3分钟付费0.2元，以后每分钟0.1元．田田和妈妈通话多长时间？
<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>