國一數學拜託大大救救十點!~

[匿名]

2014-01-30 11:18 pm

(1)化簡-2(5-3x)-[3(x-1)-5]=?
(2)園遊會時小華班上賣薯條和可樂薯條每包可賺7元可樂每杯可賺6元若已知賣出的可樂杯數比薯條包數的3倍多25 且共賺2400元請問薯條賣出多少包?可樂賣出多少杯?
(3)現有濃度a%的食鹽水800公克加入200公克的水稀釋後心的食鹽水濃度為b% 則b=?
(4)6加3/2-6( )/3=23/6 求( )
(5)不及格的人數占了全班的1/3 及格但不到80分的人占了全班一半又3人 80以上的只有三人求班上不及格有多少人?
(6)若x=-0.07 則24x-(5-19x)的值
(7)甲乙丙三人量體重已知甲比丙重8公斤甲丙體重和是乙的2倍設甲的體重為x公斤那甲乙丙三人的體重和是多少公斤?
(8)解方程式4{5(6x-3)-2}-1=87 x=?
(9)解下列各一元一次方程式
(1) 3(x-4)-5(2x-1)=7
(2)12-3{x-(1/4x加5)}=1/6x-89
(10)阿芳利用一些罐子裝糖果若每個罐子裝13顆則會有3顆沒有罐子裝若改成每個罐子裝16顆糖果則會剩下3顆空罐子請問罐子有多少顆? 糖果有多少顆?
(11)沿河的同岸有甲乙兩鎮若船在靜水中時速為10公里水流時速為2公里往返甲乙兩鎮需5小時則甲乙兩鎮相距多少公里?
(12)以等速度行駛的捷運列車若接速度提高25% 則相同距離的行車時間可節省a%求a為多少?
(13)兩支長度一樣的蠟燭其中一隻可以燃燒4小時力一隻可以燃燒6小時若兩支蠟燭同時點燃則經過多少小時其中一隻的長度是另一支長度的2倍求多少?
(14)圓形公園一圈是800公尺小華騎車速率是每分鐘200公尺小嫻慢跑的速率是每ˇ分鐘120公尺若兩人同時同地出發同方向繞公園當小華追上小嫻十至少需要多少分鐘?
以上都需計算過程

回答 (1)

Denny

2014-01-31 4:58 am

✔ 最佳答案

1) -2(5-3x)-[3(x-1)-5]= -10+6x-(3x-3-5) = -10+6x-3x+3+5 = 3x-22) Let x and y be the numbers of fries andcokes were sold respectively.Accordingly, we have,y=3x+25____________(1)7x+6y=2400_________(2)Sub. (1) into (2), 7x+6(3x+25)=2400 x=90Sub. x=90 into (1),y=3(90)+25 =295Hence, he sold 90 fries and 295 cokes respectively. 3) Accordingly, we have,b=800a/(800+200)b=4a/5 (simplified) 4) Let x be the answer of the bracket.6+3/2-6x/3=23/6 -6x/3=-11/3 6x=11 x=11/6 5)Let x be the number of failed students,and the number of whole class is 3x.3x/2+3+3+x=3x 3x/2-2x=-6-x=-12 x=12Hence, the number of failed students is 12. 6) x=-0.07(given), then sub. it into theexpression 24x-(5-19x),we have,24(-0.07)- [5-19(-0.07]= -1.68-6.33 = -8.01 7) Let x kg be the weight of A, and weightof C is (x-8)kg, the weight of B is (x+x-8)/2.The sum of their weights=x+(x-8)+[(x+x-8)/2] kg =2x-8+(2x-8)/2kg =(3x-12)kg (it’s an algebraexpression) 8) 45[ (6x-3)-2]-1=87 45(6x-5)=88 6x-5=88/45 6x=313/45 x=313/270 9)(i) 3(x-4)-5(2x-1)=7 3x-12-10x+5 =7 -7x=14 x=-2 (ii) 12-3[x-(1/4x+5)] =1/6x-89 12-3(x-x/4-5)=x/6-89 12-3x+3x/4+15=x/6-89 -3x+3x/4-x/6=-89-12-15 -29x/12=-116 x=48 10) Let x be the number of the cans.Accordingly, we have, 13x+3=16(x-3) x=17Hence, there are 17 cans. And there are candies=13*17+3=224 /=16(17-3)=224 11) Let x km be the distance between places A and B. Accordingly, we have,x/(10+2)+x/(10-2)=5 Solve: x=24Hence, the distance between places A and B is 24 km. 12) The time required will decrease 25%. 13) After burning 3 hours, one was left 1/4, another one was left3/6.Hence, after burning 3 hours, one of the candles is twice as anotherone. 14) The time required=800m/(200m/min-120m/min)=10 mins

參考: 劍鋒

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國一數學拜託大大救救 十點!~

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國一數學拜託大大救救十點!~