急急急!!!求答案，中二maths~~10點*2

第一題
1. actual length of road in km
given: road on map = 4.5cm
ratio: 1 : 50000

therefore, actual length = 4.5*50000 = 225000 cm
convert to km = 225000cm = 2250m = 2.25km

2. according to question1, actual length = 2.25km = 225000cm
while ratio = 1: 250000
therefore, length on map = 225000cm/250000cm = 0.9cm

第二題
a = amy
b = betty
c = cat
a:b = 2:1
c:b = 3:1
ａ：ｂ
　　ｂ：ｃ
＿＿＿＿＿
２：１
　　１：３
＿＿＿＿＿
２：１：３
therefore, ratio of a:b:c = 2:1:3
substitute x into ratio
that is a got 2x of the money
b got x of the money
c got 3x of the money
2x + x + 3x=1200

therefore, x = 200
in conclusion, a gets 2x = $400, b gets $200, c gets $600.

2007-11-07 22:28:18 補充：
樓上兩位答案不對啊.因為cm 要先轉為m 才可轉kmconvert to km = 225000cm = 2250m = 2.25km這才是對啊!!!

第一題：
(1) (4.5)cm / a = 1 / 50000
a = [(4.5 x 50000) / (100 x 1000)] km
=> actual length of the road in km = 2.25km

(2) y / 2.25km = 1 / 250000
y = [(2.25 / 250000) x (100 x 1000)]cm
=> its length in cm on a map = 0.9cm

第二題：
A : B = 2 : 1 =>> A = 2B
C : B = 3 : 1 =>> C = 3B
A + B + C = $1200
2B + B + 3B = $1200
6B = $1200
B = $200, A = 2B = $400, C = 3B = $600

第一題
(1)
actual length of the road=(4.5X50000) =225000cm=2250m=2.25km

(2)
since actual length of the road is 225000cm
i.e. The length in cm on a map of scale is 0.9 cm

1(1): Actual length=(4.5 x 50000)cm=225000cm=225km
1(2): Its length in cm=225000/250000=0.9cm

2: Amy:Betty:Cat=2:1:3
Amy gets=$1200 x 2/6=$400
Betty gets=$1200 x 1/6=$200
Cat gets=$1200 x 3/6=$600

1(1): Actual length=(4.5 x 50000)cm=225000cm=225km
1(2): Its length in cm=225000/250000=0.9cm

2: Amy:Betty:Cat=2:1:3
Amy gets=$1200 x 2/6=$400
Betty gets=$1200 x 1/6=$200
Cat gets=$1200 x 3/6=$600