八年级数学应用题
\u516b\u5e74\u7ea7\u6570\u5b66\u8ba1\u7b97\u9898\u548c\u5e94\u7528\u9898\u67d0\u6821\u7ec4\u7ec7\u5e08\u751f\u6625\u6e38,\u5982\u679c\u5355\u72ec\u79df\u752845\u5ea7\u5ba2\u8f66\u82e5\u5e72\u8f86,\u521a\u597d\u5ea7\u6ee1;\u5982\u679c\u5355\u72ec\u79df\u752860\u5ea7\u5ba2\u8f66,\u53ef\u5c11\u79df\u4e00\u8f86,\u4e14\u4f59
30\u4e2a\u7a7a\u5ea7\u4f4d:
(1)\u6c42\u8be5\u6821\u53c2\u52a0\u6625\u6e38\u7684\u4eba\u6570.
(2)\u5df2\u77e545\u5ea7\u5ba2\u8f66\u7684\u79df\u91d1\u4e3a\u6bcf\u8f86250\u5143,60\u5ea7\u5ba2\u8f66\u7684\u79df\u91d1\u4e3a\u6bcf\u8f86300\u5143,\u8fd9\u6b21\u6625\u6e38\u540c\u65f6\u79df\u7528\u8fd9\u4e24\u79cd\u5ba2\u8f66,\u5176\u4e2d60\u5ea7\u5ba2\u8f66\u6bd445\u5ea7\u5ba2\u8f66\u591a\u79df1\u8f86,\u6240\u4ee5\u79df\u91d1\u6bd4\u5355\u72ec\u79df\u7528\u4e00\u79cd\u5ba2\u8f66\u8981\u7701,\u6309\u8fd9\u79cd\u65b9\u6848\u9700\u7528\u79df\u91d1\u591a\u5c11\u5143?
\u5206\u6790\uff1a\u672c\u4f8b\u76f8\u7b49\u5173\u7cfb\u6709\u4e24\u4e2a\uff1a\uff081\uff09\u5355\u72ec\u79df\u752845\u5ea7\u5ba2\u8f66\u8f86\u6570\uff1d\u5355\u72ec\u79df\u752860\u5ea7\u5ba2\u8f66\u8f86\u6570\uff0b1\uff1b\uff082\uff09\u5e08\u751f\u4eba\u6570\uff1d45\u5ea7\u5ba2\u8f66\u8f86\u6570\u00d745\uff1d60\u5ea7\u5ba2\u8f66\u8f86\u6570\u00d760\uff0d30\uff0c\u5c5e\u4e8e\u7ed3\u8bba\u5f00\u653e\u8bd5\u9898\u3002\u79df\u8f66\u65b9\u6848\u6ee1\u8db3\u4e24\u4e2a\u6761\u4ef6\uff1a\uff081\uff09\u79df\u7528\u4e24\u79cd\u5ba2\u8f66\uff1b\uff082\uff09\u79df\u91d1\u6bd4\u5355\u72ec\u79df\u7528\u4e00\u79cd\u5ba2\u8f66\u8981\u8282\u7701\u3002
\u89e3\uff1a\uff081\uff09\u65b9\u6cd5\u4e00\uff1a\u8bbe\u8be5\u6821\u53c2\u52a0\u6625\u6e38\u7684\u4eba\u6570\u4e3ax\uff0c\u7531\u9898\u610f\uff0c\u5f97
x/45=(x+30)/60\uff0b1\u3002\u89e3\u5f97\uff1d270\u3002
\u65b9\u6cd5\u4e8c\uff1a\u8bbe\u79df\u752845\u5ea7\u7684\u5ba2\u8f66x\u8f86\uff0c\u5219\u79df\u752860\u5ea7\u5ba2\u8f66\uff08x\uff0d1\uff09\u8f86\uff0c\u7531\u9898\u610f\u53ef\u5217\u51fa\u65b9\u7a0b\u4e3a
45\uff1d60\uff08x\uff0d1\uff09\uff0d30\u3002\u89e3\u4e4b\uff0c\u5f97\uff1d6\u3002
\u6240\u4ee5\uff0c\u53c2\u52a0\u6625\u6e38\u4eba\u6570\u4e3a45\u00d76\uff1d270\uff08\u4eba\uff09\u3002
\uff082\uff09\u65b9\u6cd5\u4e8c\uff1a\u8bbe\u79df\u752845\u5ea7\u5ba2\u8f66y\u8f86\uff0c\u5219\u79df\u752860\u5ea7\u5ba2\u8f66\uff08y\uff0b1\uff09\u8f86\uff0c\u7531\u4e8e\u5355\u72ec\u752845\u5ea7\u5ba2\u8f66\u65f6\uff0c\u9700\u7528270/45\uff1d6\uff08\u8f86\uff09\uff0c\u9700\u7528\u79df\u91d1250\u00d76\uff1d1 500\uff08\u5143\uff09\uff0c\u800c\u5355\u72ec\u79df\u752860\u5ea7\u5ba2\u8f66\u65f6\uff0c\u9700\u8f665\u8f86\uff0c\u4e5f\u9700\u79df\u91d11 500\u5143\u3002\u7531\u9898\u610f\uff0c\u5f97
250y\uff0b300\uff08y\uff0b1\uff09\uff1c1 500\u3002\u89e3\u4e4b\uff0c\u5f97\uff1c24/11\u3002
\u56e0\u79df\u7528\u7684\u8f66\u8f86\u6570\u5e94\u4e3a\u6b63\u6574\u6570\uff0c\u6240\u4ee5y\uff1d1\u62162\u3002
\u5f53y\uff1d1\u65f6\uff0cy\uff0b1\uff1d2\uff0c\u521945\u00d71\uff0b60\u00d72\uff1d165\uff1c270\uff0c\u4e0d\u5408\u9898\u610f\uff0c\u820d\u53bb\u3002
\u5f53y\uff1d2\u65f6\uff0cy\uff0b1\uff1d3\uff0c\u521945\u00d72\uff0b60\u00d73\uff1d270\uff0c\u7b26\u5408\u9898\u610f\uff0c\u8fd9\u65f6\u9700\u79df\u91d12\u00d7250\uff0b3\u00d7300\uff1d1 400\uff08\u5143\uff09\u3002
\u7b54\uff1a\u8be5\u6821\u53c2\u52a0\u6625\u6e38\u7684\u4eba\u6570\u4e3a270\u4eba\uff0c\u9700\u8981\u79df\u91d11 400\u5143\u3002
\u4e0a\u9762\u9519\u7684\uff0c\u770b\u8fd9\u91cc\uff0c100%\u6b63\u786e\uff1a
1\uff0c\u8bbe\u7532\u7684\u901f\u5ea6\u4e3aX\uff0c\u4e59\u7684\u901f\u5ea6\u4e3aY\u3002\u5219\u6709\uff1a
9Y-4X=12 , 9Y/X=4X/Y , \u89e3\u5f97X=6\u6216\u8005X=-1.2\uff08\u820d\u53bb\uff09\uff0c\u5219Y=4\uff0cS=4X+9Y=60
\u601d\u8def\uff1a\u76f8\u9047\u540e\u7532\u518d\u8d704\u5c0f\u65f6\u5230B\u5730\uff0c\u8fd9\u6bb5\u8def\u7a0b\u4e3a4X\uff0c\u5176\u5b9e\u8fd9\u6bb5\u8def\u7a0b\u5c31\u662f\u4e59\u8d70\u8fc7\u6765\u7684\u8def\u7a0b\uff0c\u76f8\u9047\u540e\u4e59\u518d\u8d709\u5c0f\u65f6\u5230\u8fbeA\u5730\uff0c\u8fd9\u6bb5\u8def\u7a0b\u4e3a9Y\uff0c\u5176\u5b9e\u8fd9\u6bb5\u8def\u7a0b\u5c31\u662f\u7532\u8d70\u8fc7\u6765\u7684\u8def\u7a0b\uff0c\u56e0\u4e3a\u76f8\u9047\u65f6\u7532\u6bd4\u4e59\u591a\u8d7012\u7c73\uff0c\u6240\u4ee59Y-4X=12\u3002
\u7532\u4e59\u76f8\u9047\u65f6\u6240\u7528\u7684\u65f6\u95f4\u76f8\u7b49\uff0c\u6240\u4ee5\u7532\u7684\u8def\u7a0b\u9664\u4ee5\u7532\u7684\u901f\u5ea6\u7b49\u4e8e\u4e59\u7684\u8def\u7a0b\u9664\u4ee5\u4e59\u7684\u901f\u5ea6\uff0c\u53739Y/X=4X/Y\u3002
2\uff0c\u8bbe\u56e2\u5458\u6709X\u4eba\uff0c\u975e\u56e2\u5458\u6709Y\u4eba\uff0c\u975e\u56e2\u5458\u6350\u4e66Z\u672c\uff0c\u5219\u56e2\u5458\u6350\u4e66Z+8\u672c\uff0c\u5219\u6709\uff1a
Y-X=10 , XZ+(Z+8)Y=760 , (Z+8)Y-XZ=40\u3002\u89e3\u5f97\uff0cZ=12,Y=30,X=20\u3002
\u770b\u4e0d\u61c2\u6216\u8005\u4e0d\u4f1a\u89e3\u65b9\u7a0b\u95ee\u6211\uff0cQQ\uff1a345044302
甲队单独完成此项工程需：1÷（1/24-1/120）=30(天）
甲24天+乙24天=120万元
甲1天+乙1天=5万元
甲20天+乙20天=100万元
甲20天+乙40天=110万元
乙1天：（110-100）÷（40-20）=0.5（万元）
甲1天：5-0.5=4.5（万元）
甲队单独完成此项工程需费用：4.5X30=135(万元）
乙队单独完成此项工程需费用：120x0.5=60(万元）
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