batch of washing machines and color TVs were shipped from the appliance store. The number of color TV sets is three times that of washing machines. Now, an average of 10 washing machines and 15 color TV sets are sold every day. When the washing machines are sold out, there are still 120 color TV sets that have not been sold. How many washing machines were shipped in total?
家电商场运来一批洗衣机和彩电，彩电的台数是洗衣机的3倍，现在每天平均售出10台洗衣机和15台彩电，当洗衣机售完时，彩电还剩下120台没有售出，家电商场共运来洗衣机多少台？
<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<gadget id="calculator">30 - 15</gadget>
<output>15</output>

<gadget id="calculator">120 / 15</gadget>
<output>8</output>

<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">15 * 8</gadget>
<output>120</output>

<gadget id="calculator">80 + 120 + 120</gadget>
<output>320</output>

<result>320</result>