There is a pile of black and white pieces, the number of black pieces is twice that of white pieces, each time 3 pieces of white pieces are taken out, and 5 pieces of black pieces are taken out. When the white pieces are taken out, there are still 20 pieces of black pieces left. Then how many pieces are there in total in this pile of chess pieces.
有一堆黑白棋子，黑棋的粒数是白棋的2倍，每次从中取出白棋3粒黑棋5粒，白棋恰好取完时黑棋还剩20粒．则原来这堆棋子共有多少粒．
<gadget id="calculator">6 - 5</gadget>
<output>1</output>

<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">20 * 3 * 3</gadget>
<output>180</output>

<result>180</result>