A pile of colored balls, red and yellow. There are 49 red balls in the first 50 balls counted; there are 7 red balls in every 8 balls counted later. Count until the last 8 balls, which is exactly the end of the count. If at least 90% of the counted balls are red, what is the maximum number of balls in this pile?
一堆彩色球，有红、黄两种颜色．首先数出的50个球中有49个红球；以后每数出的8个球中都有7个红球．一直数到最后8个球，正好数完．如果在已经数出的球中红球不少于90%，那么这堆球的数目最多只能有多少个？
<gadget id="calculator">20 * 8</gadget>
<output>160</output>

<gadget id="calculator">50 + 160</gadget>
<output>210</output>

<result>210</result>