中二數學~不懂怎計請幫幫手－yffuhxy的部落格

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中二數學~不懂怎計請幫幫手

發問:

(4). A chicken and a duck cost $45 , while 5 chickens and 6 ducks cost $250. Find the price of each animal. 5) Three pens and two rubbers together cost $52 .The cost of a rubber is two-thirds the cost of a pen . Find the cost of a pen and a rubber .6) Two aticles cost $51 together and one is $3 cheaper than the... 顯示更多 (4). A chicken and a duck cost $45 , while 5 chickens and 6 ducks cost $250. Find the price of each animal. 5) Three pens and two rubbers together cost $52 .The cost of a rubber is two-thirds the cost of a pen . Find the cost of a pen and a rubber . 6) Two aticles cost $51 together and one is $3 cheaper than the other. Find the cost of each atricle . 7)One-sixth of the sum of two numbers is 3, and eight times their difference is 32. Find the numbers.

最佳解答:

4.)A chicken and a duck cost $45 ......1) 5 chickens and 6 ducks cost $250......2) 5chicken and 5 duck cost $225 .....3) 2)-3)1 DUCK=25 A chicken =45-25=20 2007-02-08 15:47:58 補充： 5)Three pens and two rubbers together cost $52 The cost of a rubber is two-thirds the cost of a pen 2/3PEN=1RUBBER Three pens and 4/3 PENS COST$52 4.1/3PENS=52 A PEN= $12 A RUBBER=2/3PEN =$8 2007-02-08 15:50:41 補充： Two aticles cost $51 ONE OF THEM LESS $3THE HIGH PRICES is($51＋$3)/2＝$27 ANOTHER＝$27－$3＝＄２４ 2007-02-08 15:56:41 補充：７）ｉｄｏｎｔｕｎｄｅｒｓｔａｎｄｗｈａｔｙｏｕａｓｋ 2007-02-08 16:09:41 補充：７）One-sixth of the sum of two numbers is 3the sum of two numbers ＝１８and eight times their difference is 32（ｎｏｔｓｕｒｅ） 2007-02-10 12:53:00 補充： 8a－8b＝32a＋b＝18．．．．１）ａ－ｂ＝４．．．２）ａ＝１８－ｂ．．．３）ｔａｋｅ３）ｔｏ２）１８－ｂ－ｂ＝４１８－４＝２ｂ１４＝２ｂｂ＝７ａｉｓ１８－７＝１１ｔｈｅｔｗｏｎｕｍｂｅｒｓｉｓ７ａｎｄ１１

其他解答:

let $x be the price of chicken , $y be the price of duck x+y=45...(1) 5x+6y=250...(2) x=45-y...(3) sub(3) into (2) 5(45-y)+6y=250 225-5y+6y=250 y=25 x=20 let $a be the cost of pen,$b be the cost of rubber 3a+2b=52...(1) b=2/3a...(2) sub(2)into(1) 3a+2(2/3a)=52 a=12 b=8 let $c be the cost of article1 ,$d be article2 c+d=51...(1) c-3=d...(2) sub(2)into(1) c+c-3=51 c=27 d=24