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ç§è¥¿çº¢æ¿çé¢ç§¯ï¼600 X 30% = 180(å¹³æ¹ç±³)
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10份ä¸ç1ä»½æ¯ 420 / 10 = 42ï¼å¹³æ¹ç±³ï¼
ç§é»ççé¢ç§¯ = 42 x 7 = 294(å¹³æ¹ç±³)
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600 x (1-- 30%) x 7 / (7 +3 )
= 600 x 0.7 x 0.7
= 294 (å¹³æ¹ç±³)
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