F.1數學問題~~急急急!請幫幫手!20點!－aptzmcv的部落格

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F.1數學問題~~急急急!請幫幫手!20點!

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全部都要用方程答,要列出所有steps1)72 marbles are divided into two groups.7 times the number of marbles in the smaller group is equal to 5 times that in the larger group.Find the number of marbles in the smaller group.2)The total age of Hebrew and his son is 51. 3 years ago,Hebrew is 8 times as old as his son.Find the... 顯示更多全部都要用方程答,要列出所有steps 1)72 marbles are divided into two groups.7 times the number of marbles in the smaller group is equal to 5 times that in the larger group.Find the number of marbles in the smaller group. 2)The total age of Hebrew and his son is 51. 3 years ago,Hebrew is 8 times as old as his son.Find the current age of Hebrew's son. 3)Concert tickets in $400,$200 and $100 each are available for sale.The number of $200 tickets sold is 4 times as many as that of $400 tickets.The number of $100 tickets sold is 380 more than that of $200 tickets.If the total income from the sale tickets is $86000,how many 4400 tickets are sold? 4)Bobby buys x pieces of fruit tarts and eats 1/4 of them.His brothers and sisters eat 7 pieces in total and there are 2 pieces left.Find the value of x. 5)The total price of 24 books is $405.Some of them are sold at $15 each and the others at $20 each.Find the number of books that are sold at $15 each. 6)Tork has $72.Sally has $12.In order to let Sally have 3 times the amount of York, how much should York give Sally? 7)A sum of money is planned to be evenly shared among 10 persons.Due to the absence of2 persons, each person present can get $30 more.Find the sum of money. 8)Carl has $9 more than David does.Hilbert has 1/3 of the amount of Carl.If they have a total amount of boys and girls there. 9)There are 42 students in S1A.The number of boys is 4/3 times of girls.Find the respective number of boys and girls there. 答得幾多得幾多,1題都好,真係唔識的都試吓,真係好需要你們的幫忙!!thanks. 更新: 10)Scot has $(3x+2).Anson has $(4x-1).Karen has $(s+20).If they have $69 in total , find x. 15)The length of line AB is 27cm. Line AX is 2x cm.Line XY is (3x-2)cm.Line YB is (x+5)cm.Find the length of line AX. 更新 2: 16)3a+(2a-1)+(4a-2)=91,Find the value of a. 17)(2x-6)+1/2x=14,Find the value of x. 19)After subtracting 8 from a number, the difference multiplied by 9 is 108.Find the number. 20)Simon is 32 years older than his son.After 6 years,the sum of their ages will be 50.Fid the current age of Simon's son. 更新 3: 8)Carl has $9 more than David does.hilbert has 1/3 of the amount of Carl.If they have a tital amount of $61,how much does each of them have?

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1. Let x be the number of marbles in the smaller group, then (72-x) is that in the larger group. 7x = 5(72-x) ..... (7 times small gp = 5 times large gp) 7x = 360 - 5x 12x = 360 x = 30 There are 30 marbles in the smaller group. 2. Let x be the current age of Hebrew's son, then (51-x) is that of Hebrew. 8(x-3) = 51-x-3 ..... (8 times son (3 yrs ago) = Hebrew (3 yrs ago)) 8x - 24 = 48 - x 9x = 72 x = 8 Hebrew's son is now 8 years old. 3. Let x be the number of $400-tickets sold, then 4x is that of $200-tickets sold and 4x+380 is that of $100-tickets sold. 400x + 200(4x) + 100(4x + 380) = 86000 400x + 800x + 400x + 38000 = 86000 1600x = 48000 x = 30 30 $400-tickets are sold. 4. x - x/4 - 7 = 2 ...... (original - Bobby - brothers&sisters = 2) x - 0.25x = 9 0.75x = 9 x = 12 5. Let x be the number of books that are sold at $15 each, then (24 - x) is the number of books that are sold at $20 each. 15x + 20(24 - x) = 405 15x - 20x + 480 = 405 -5x = -75 x = 15 15 books are sold at $15 each. 6. Let $x be the money that York should give Sally. 3(72 - x) = 12 + x 216 - 3x = 12 + x 204 = 4x x = 51 York should give Sally $51. 7. Let $x be the money that each people can get originally. 10x = (10-2) (x+30) 10x = 8(x+30) 10x = 8x + 240 2x = 240 x = 120 The sum of money = 120*10 = $1200. 8. What is the question? 9. Let x be the number of girls in the class, then (42 - x) is the number of boys in the class. 4x/3 = 42 - x x = (3/4)(42 - x) x = 31.5 - 3x/4 x + 3x/4 = 31.5 x + 0.75x = 31.5 1.75x = 31.5 x = 18 There are 18 girls and 18(4/3) = 24 boys in the class. 2009-11-22 20:40:10 補充： 10. 3x+2 + 4x-1 + x+20 = 69 8x + 21 = 69 8x = 48 x = 6 15. I think the meaning of the question is that X and Y are points on AB, then, AX + XY + YB = AB 2x + 3x-2 + x+5 = 27 6x + 3 = 27 6x = 24 x = 4 Since AX = 2x, so AX = 2*4 = 8cm 2009-11-22 22:33:54 補充： 8. Let $x be the money that Hilbert has, then $(3x) is the money Carl has and $(3x-9) is the money David has. x + 3x + 3x-9 = 61 7x - 9 = 61 7x = 70 x = 10 Hilbert has $10, Carl has 3*10 = $30, David has 30 - 9 = $21.

其他解答:

1)Let m be the number of marbles in the smaller group 7m=5(72-m) 7m=360-5m 12m=360 m=30 Therefore,there hace 30 marbles in the smaller group 2)Let x be the current age of Hebrew's age 8(x-3)=51-p-3 8x-24=51-9-3 9p=75-3 p=8 Therefore,Hebrew's son is 8 years old 7)Let $x be the sum of money x/10+30=x/8 8x-10x=-2400 x=1200 Therefore,The sum of money is $12008410E5B82AE3BBEE