There are 500 grams of brine with a concentration of 70% and 300 grams of brine with a concentration of 50%. What is the concentration after mixing the two?
现有浓度为70%的盐水500克，浓度为50%的盐水300克，将两者混合之后浓度为多少？
<gadget id="calculator">70 / 100</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">500 * (7/10)</gadget>
<output>350</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">300 * (1/2)</gadget>
<output>150</output>

<gadget id="calculator">350 + 150</gadget>
<output>500</output>

<gadget id="calculator">500 + 300</gadget>
<output>800</output>

<gadget id="calculator">500 / 800</gadget>
<output>5/8 = around 0.625</output>

<result>5/8 = around 0.625</result>