A bag contains 70 balls, of which 20 are red, 20 green, 20 yellow, and the rest are black and white. In order to ensure that the drawn balls contain at least 10 balls of the same color, the minimum number of balls must be taken from the bag.
某袋内装有70只球，其中20只红球，20只绿球，20只黄球，其余是黑球和白球．为确保取出的球中至少包含有10只同色的球，最少必须从袋中取出多少只球．
<gadget id="calculator">70 - 20 - 20 - 20</gadget>
<output>10</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">10 + 27 + 1</gadget>
<output>38</output>

<result>38</result>