Wang Ming used his mobile phone to make a call to his mother who was working in Guangzhou, the cost was 0.4 yuan per minute, and the call fee was 6.4 yuan. How many minutes did Wang Ming spend on the phone?
王明用手机给在广州工作的妈妈打了一个电话，每分钟0.4元，通话费是6.4元．王明打电话的时间是多少分？
<gadget id="calculator">6.4 / 0.4</gadget>
<output>16</output>

<result>16</result>