A supermarket sells an average of 50 bottles of mineral water every day. How many bottles of mineral water were sold in the first quarter of this year?
某超市平均每天卖出矿泉水50瓶，今年第一季度共卖出矿泉水多少瓶．
<gadget id="calculator">31 + 28 + 31</gadget>
<output>90</output>

<gadget id="calculator">90 * 50</gadget>
<output>4_500</output>

<result>4_500</result>