英文數學文字題(方程)(4題)(20分)－hzb53jl55v的部落格

標題:

英文數學文字題(方程)(4題)(20分)

發問:

(用方程)1.In a supermarket, the price of an apple is $2.5, and a orange is $3. Alan got $2 left after buying some apples. However, her would need $2 more if he wanted to buy the same number of oranges. Find the number of apples he bought.2. Jane bought x tarts,she ate 1/4(四分之一)of them,then her brother and sister... 顯示更多 (用方程) 1.In a supermarket, the price of an apple is $2.5, and a orange is $3. Alan got $2 left after buying some apples. However, her would need $2 more if he wanted to buy the same number of oranges. Find the number of apples he bought. 2. Jane bought x tarts,she ate 1/4(四分之一)of them,then her brother and sister ate 7 tarts and 2 tarts were left.Find the value of x. 另外2題之後打~ 更新: 3.1/4(四分之一)of a mother's age is 1 year less than 1/2(二分一)of her daughter's age. If the sum of their ages is 62, fing their ages. 4.The sum of 2 times a number and 6 is divided by3. If the result is12,find the number. 更新 2: 第3題忽略 #@39 其實應該係 daughter一個posofivess s(daughter,s)

最佳解答:

1) Let x be the number of apples Alan bought (ie the number of oranges he bought also) Let y be the total money Alan originally has {y - 2.5x = 2 -------(1) [總金錢 - X咁多個值$2.5既apple = 淨番 2蚊] {y+2 - 3x = 0 ---------(2) [ 總金錢 + $2 - X咁多個值$3既orange = 0 ] From (1) y = 2 + 2.5x Sub y = 2 + 2.5x into (2) 2 + 2.5x + 2 - 3x = 0 0.5x=4 x=8 Thus the number of apples he bought is 8. 2) [X x 1/4] - 7= 2 { 1開始 Jane 食左 X中既1/4.. 之後佢brother同sister食左7個(所以-)} X x 1/4 = 9 X = 36 The value of X is 36. 3) M = mother's age, D= Daughter's age {M x 1/4 + 1 = D x 1/2 ------(1) [ "A is 1 year less than B" 即係 "B比A多1年" , 所以 A 要+1年先= B] {M + D = 62 ---------- (2) From (2) M = 62 - D ------(3) Sub (3) into (1) [(62-D)/4] + 1 = D/2 4 times the equation 62-D + 4 = 2D 66=3D D = 22 When D = 22, M = 40. 4) (2N + 6)/3 = 12 2N + 6 = 36 N=15 2008-02-06 16:43:24 補充： oops sorry..#2 果題我錯了..

其他解答:

1. let the number of apples he bought be X 2.5X+2+2=3X 0.5X =4 X=8 2. (1-1/4)*X-7=2 3/4X=9 X=12 3. let X and Y be the ages of the mother and her daugter repectively a. X+Y=62 b. 1/4X+1=1/2Y multiply equation (b) by 4, we get X+4=2Y equation (a) - equation (b), we get Y-4=62-2Y 3Y =66 Y=22 if Y=22,X=62-22=40 4. let the number be X (2X+6) / 3 = 12 2x= 30 X= 15