1. if a:b = 2:3, find 5a + 2b over 3a-b
2. Given that 3x =4y and 3y=5z, find x: y: z
maths F.1
2008-10-22 5:41 am
回答 (2)
2008-10-22 7:22 am
✔ 最佳答案
1. a : b = 2 : 3
Let a = 2k and b = 3k
[5a + 2b]/[3a - b]
= [5(2k) + 2(3k)]/[3(2k) - (3k)]
= [10k + 6k]/[6k - 3k]
= (16k)/(3k)
= 16/3
=====
2.
3x = 4y
x/4 = y/3
x : y = 4 : 3
x : y = 20 : 15 ...... (1)
3y = 5z
y/5 = z/3
y : z = 5 : 3
y : z = 15 : 9 ...... (2)
Compare (1) and (2):
x : y : z = 20 : 15 : 9
=
2008-10-22 6:58 am
答案:
1.)
=5/1/3
2.)
X=170
Y=127.5
Z=102
2008-10-21 23:07:46 補充：
Sorry=.=
做錯.......
Z應該=76.5
1.)
=5/1/3
2.)
X=170
Y=127.5
Z=102
2008-10-21 23:07:46 補充：
Sorry=.=
做錯.......
Z應該=76.5
參考: 自己做
收錄日期: 2021-04-23 23:05:15
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