There are a total of 800 black goldfish and red goldfish in the fish pond. After fishing out 80 black goldfish and 80 red goldfish respectively, (5/7) of the remaining black goldfish is equal to (5/9) of the remaining red goldfish ． How many black goldfish were there in the fish pond?
鱼池中有黑金鱼和红金鱼共800条，捞出黑金鱼和红金鱼各80条后，剩下的黑金鱼条数的(5/7)等于剩下红金鱼条数的(5/9)．鱼池中原有多少条黑金鱼．
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(5/7) * 80</gadget>
<output>400/7 = around 57.142857</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">(5/9) * 800</gadget>
<output>4_000/9 = around 444.444444</output>

<gadget id="calculator">(5/9) * 80</gadget>
<output>400/9 = around 44.444444</output>

<gadget id="calculator">(4_000/9) - (400/9)</gadget>
<output>400</output>

<gadget id="calculator">(400/7) + 400</gadget>
<output>3_200/7 = around 457.142857</output>

<gadget id="calculator">(5/7) + (5/9)</gadget>
<output>80/63 = around 1.269841</output>

<gadget id="calculator">(3_200/7) / (80/63)</gadget>
<output>360</output>

<result>360</result>