Uncle Wang has applied for a mobile phone card. The charging standard of this mobile phone card is: a fixed fee of 10 yuan per month, and a fee of 0.2 yuan per minute of calls (including receiving calls). Uncle Wang has deposited 50 yuan in the card, how many minutes can he talk this month?
王叔叔办理了一张手机卡，这种手机卡的收费标准是：每月固定收费10元，此外每通话1分钟收费0.2元(接听电话也包含在内)．王叔叔在卡中存了50元钱，本月他可以通话多少分钟？
<gadget id="calculator">50 - 10</gadget>
<output>40</output>

<gadget id="calculator">40 / 0.2</gadget>
<output>200</output>

<result>200</result>