小六數學思考題

X= 豬
Y=羊
X+Y=500
3/4 (X)=Y+60
SO. 豬有320隻, 羊有180隻

180隻豬和320隻羊

設牧場有豬 m 隻 , 羊有 ( 500 - m ) 隻

m x ( 1 - 1/4 ) = ( 500 - m ) + 60

3/4 m = 500 - m + 60

m + 3/4 m = 500 + 60
1 /3 /4 m = 560

m = 560 ÷ 1 /3 /4
m = 560 x 4 / 7
m = 320

∴ 原有羊 ( 500 - 320 ) = 180 隻 , 豬 = 320 隻

設豬的數量為a , 羊的數量為b

a+b=500 --(1)

3/4 a=60+b --(2)

a=500-b --(3)

把(3)代進(2):3/4(500-b)=60+b

375-0.75b=60+b

375-60=b+0.75b

315=1.75b

b=180

再代b=180入(1):a+180=500

a=320

所以，有320隻豬和180隻羊。

Let x be the no. of pig and y be the no. of sheep.
x+y=500.........(1)
x(3/4)=y+60........(2)
From (1),
x=500-y.........(3)
From (2),
3x/4=y+60
3(500-y)=4y+240
1500-3y=4y+240
7y=1260
y=180
From (3),
x=500-(180)
x=320

so
牧場共有320隻豬和180隻羊

設羊和豬分別有x和y隻
x+y=500..[1]
(1-1/4)x=y+60..[2]

form[1]
x+y=500
x=500-y..[3]

put [3] into [2]
(1-1/4)x=y+60
3/4(500-y)=y+60
375-3/4y=y+60
315=7/4y
y=180..[4]

put [4] into [3]
x=500-180
x=320

so,原有羊320隻和豬180隻

2007-01-05 23:52:11 補充：
sori..調轉左=口='''設豬和羊分別有x和y隻x y=500..[1](1-1/4)x=y 60..[2]form[1]x y=500x=500-y..[3]put [3] into [2](1-1/4)x=y 603/4(500-y)=y 60375-3/4y=y 60315=7/4yy=180..[4]put [4] into [3]x=500-180x=320so,原有豬320隻和羊180隻

x=豬
y=羊
1: 500=x+y
2: 3x/4=y+60

將1.轉成: x=500-y
將改了的1.代入2.即: 3(500-y)/4=y+60
1500-3y=(y+60)*4
1500-3y=4y+240
7y=1260
y=180
將答案放回1.: x=500-180
x=320
答案: 180隻豬和320隻羊