Xiaoyue plans to spend several days saving money for summer travel. From now on, if she saves 10 yuan a day, she will be short of 120 yuan; if she saves 15 yuan a day, she will be 30 yuan more than expected. How much money does Xiaoyue expect to live with?
小悦打算用若干天为暑假旅游存钱，从现在起如果每天存10元，会缺少120元；如果每天存15元，则会比预计多出30元．小悦预计共存多少元钱．
<gadget id="calculator">120 + 30</gadget>
<output>150</output>

<gadget id="calculator">15 - 10</gadget>
<output>5</output>

<gadget id="calculator">150 / 5</gadget>
<output>30</output>

<gadget id="calculator">30 * 10</gadget>
<output>300</output>

<gadget id="calculator">300 + 120</gadget>
<output>420</output>

<result>420</result>