Mom takes Ding Ding to visit grandma in Beijing by plane. Mom's air ticket is full price of 1500 yuan. Tintin's air ticket is 750 yuan for children. Mom bought a round-trip ticket, and the price of the round-trip ticket is the same. How much is the round-trip air ticket for two people?
妈妈带丁丁坐飞机去北京看望外婆，妈妈的机票是全价1500元．丁丁的机票是儿童票750元．妈妈买的是往返机票，且往返机票价格相同．两人的往返机票一共多少元？
<gadget id="calculator">1_500 + 750</gadget>
<output>2_250</output>

<gadget id="calculator">2_250 * 2</gadget>
<output>4_500</output>

<result>4_500</result>