为鼓励居民节约用水，某市决定对居民用水收费实行“阶梯价”，即当每月用水量不超过15吨时（包括15吨），
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| （1）3元/吨，2元/吨（2） （3）63元 绛旓細锛1锛夌敱棰樻剰寰楋紝搴斾氦姘磋垂锛20脳2.3+10脳3.45+2脳4.6=89.7锛堝厓锛夛紝绛旓細灏忔槑瀹8鏈堜唤搴斾氦姘磋垂89.7鍏冿紱锛2锛夎灏忔槑瀹10鏈堜唤鐢ㄦ按x绔嬫柟绫筹紝褰撴湀鐢ㄦ按閲涓20绔嬫柟绫虫椂锛屽簲浜ゆ按璐20脳2.3=46鍏冿紱褰撴湀鐢ㄦ按閲忎负30绔嬫柟绫虫椂锛屽簲浜ゆ按璐20脳2.3+10脳3.45=80.5鍏冿紝鈭靛皬鏄庡10鏈堜唤浜ょ撼姘磋垂59.8鍏冿紝... 绛旓細璁9鏈堜唤鐨鐢ㄦ按閲鏄痻锛岀敱棰樻剰寰楋細1脳7+2脳锛坸-7锛=17锛岃В寰楋細x=12锛岀瓟锛氳繖鎴灞呮皯9鏈堜唤鐨勭敤姘撮噺涓12鍚紟 绛旓細甯冨徑灏忓瓙锛屼綘濂斤細鏍囧噯鍐咃細12脳a锛12a 鏍囧噯澶栵細锛20a-12a锛壝2a锛4锛堝惃锛夎灞呮皯杩欎釜鏈鐢ㄦ按锛12锛4锛16锛堝惃锛=== 瑙ｏ細璁捐繖涓湀鐢ㄦ按X鍚 12a锛嬶紙X锛12锛壝2a锛20a 12a锛2aX锛24a锛20a 2aX锛32a X锛16 绛旓細锛堜竴锛夛紱n=15 鍒欎负15a鍏 n>15 鍒欎负15a+(n-15)2a 锛堜簩锛夛紱鍗佹湀浠斤紱15a+40a=55a 鍗佷竴鏈堜唤锛15a+30a=45a 鍗佷簩鏈堜唤锛15a+20a=35a 绛旓細5+8=12.5鍏冿紝鐢叉埛璇ユ湀浜ゆ按璐6.9鍏冿紝璇存槑鐢叉埛璇ユ湀鐢ㄦ按涓嶈秴杩20鍚紱鍒欑敳鎴疯鏈堣秴杩10鍚ㄩ儴鍒嗙殑姘磋垂涓0.8(y-10)鍏冿紝鏍规嵁棰樻剰锛屾湁鏂圭▼锛0.8(y-10)+0.45脳10=3.15+3.75 0.8y-8+4.5=6.9 0.8y=6.9+8-4.5 0.8y=10.4 y=13 绛旓細璇ユ湀鐢叉埛鐢ㄦ按13鍚紝涔欐埛鐢ㄦ按7鍚ㄣ 绛旓細鐢ㄦ按x鍚紝搴旂即绋庤垂涓12x3+(X-12)x5=5X-24 灏忔槑锛瀵逛簬鏂圭▼x/0.3-x/0.6=1鍖栧幓鍒嗘瘝涓殑灏忔暟鐐癸紝鍙樺舰涓10x/3-10x/6=10.鍙樺舰杩囩▼涓嶆纭倄/0.3-x/0.6=1 绛夊紡涓よ竟鍚屼箻10锛屽垯寰梮/3-x/6=1 绛旓細---鈶ｅ洜姝よВ寰 a=2 锛寈=10 锛宐=3 锛屼篃鍗宠瀹氬惃鏁颁负 10 鍚紝浣庝簬 10 鍚ㄧ殑姣忓惃 2 鍏冿紝瓒呰繃 10 鍚ㄧ殑锛岃秴杩囬儴鍒嗘瘡鍚 3 鍏冦傦紙2锛鐢ㄦ按 20 鍚紝璐圭敤涓 10*2+(20-10)*3=50 鍏冦傦紙3锛夛紙涓や釜鏈堜唤寮勯鍊掍簡鍚э紵锛熷ソ濂囨摝锛29-20=9 锛9/3=3 锛屽洜姝ょ敤姘 10+3=13 鍚 銆 绛旓細瑙ｈ鐢ㄦ按閲涓篨 7+2锛圶-7)=17 X=12 琛ュ厖锛氱敤鎴灞呮皯鍏冩湀缂寸撼浜17鍏冩按璐癸紝閭ｄ箞璇ュ眳姘戜粖骞村厓鏈堜唤鐨勭敤姘撮噺涓瀹氳秴杩17m3 绛旓細鍙垎涓轰袱涓儴鍒嗘潵璁＄畻 涓嶈秴杩12鍚 a*12=12a 瓒呰繃鐨8鍚 2a*8=16a 鎵浠ユ按璐逛负12a+16a=28a 绛旓細瑙ｏ細璇灞呮皯姣忔湀鐢ㄦ按x鍚ㄣ12a+2a(x-12)=20a 2a(x-12)=8a x-12=4 x=16 鎵浠ヨ鎴峰眳姘戣繖涓湀瀹為檯鐢ㄦ按16鍚ㄣ 本站交流只代表网友个人观点，与本站立场无关 |
