Me的歲數是Dad的五分之一
Dad比Mum大3歲
Me比Mum少21歲
可否幫我找出Dad歲數的方程式,最好有答案!
一條方程式
2007-01-06 12:02 am
回答 (4)
2007-01-06 12:12 am
✔ 最佳答案
設Dad歲數為x,則Mum歲數為x-3,Me的歲數是x*(1/5)x*(1/5)=x-3-21
x/5=x-24
4x=120
x=30
即Dad歲數是30歲
2007-01-06 12:12 am
i = Me's age
M = Mum's age
D = Dad's age
then:
i = (1/5) x D
可以變成......
D = 5i.......( 1 )
D = M+3
可以變成
M = D-3...( 2 )
i = M-21...( 3 )
將(3)擺落(1)o個度, 得到:
D = 5 x ( M - 21)....(4)
再將(2)擺落(4)度:
D = 5 x ( D-3 - 21)
D = 5 x ( D-24)
D = 5D - 120
D + 120 = 5D
120 = 4D
D = 30
所以Dad ge歲數係 30
M = Mum's age
D = Dad's age
then:
i = (1/5) x D
可以變成......
D = 5i.......( 1 )
D = M+3
可以變成
M = D-3...( 2 )
i = M-21...( 3 )
將(3)擺落(1)o個度, 得到:
D = 5 x ( M - 21)....(4)
再將(2)擺落(4)度:
D = 5 x ( D-3 - 21)
D = 5 x ( D-24)
D = 5D - 120
D + 120 = 5D
120 = 4D
D = 30
所以Dad ge歲數係 30
2007-01-06 12:09 am
(1)Me = Dad/5
(2)Dad-3 = Mum
(3)Mum - 21 = Me
so Mum -21 = Dad/5
(dad-3) -21 = Dad/5
dad -24 = dad/5
5dad - 120 = dad
5dad - dad = 120
4dad = 120
dad = 30
(2)Dad-3 = Mum
(3)Mum - 21 = Me
so Mum -21 = Dad/5
(dad-3) -21 = Dad/5
dad -24 = dad/5
5dad - 120 = dad
5dad - dad = 120
4dad = 120
dad = 30
2007-01-06 12:07 am
me = x
dad = y
mum = z
x = 5y --- (1)
x + 21 = z ---(2)
x = z - 21
5y = z -21
y = (z-21)/5
dad = y
mum = z
x = 5y --- (1)
x + 21 = z ---(2)
x = z - 21
5y = z -21
y = (z-21)/5
收錄日期: 2021-04-12 15:54:51
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070105000051KK01813