猜猜年齡之謎

設富翁現時年齡為 x ; 妻子現時年齡為 y。

十六年前 , 富翁年齡是妻子的 3 倍 .
x - 16 = 3*( y - 16 ) - (1)

十六年後 ( 現在 ) , 富翁年齡為妻子的 2 倍。
x = 2y - (2)
把 x = 2y 代入 (1) ,
x - 16 = 3*( y - 16 )
2y - 16 = 3y - 48
y = 32
x = 2y = 64

因此，富翁現時年齡為 64 歲；妻子年齡為 32 歲。

一位億萬老富翁=x
年輕小姐=y
3(y-16)=x-16
2y=x
so
3(y-16)=2y-16
3y-48=2y-16
3y-48+16=2y+16
3y-32=2y
3y-32+32=2y+32
3y=2y+32
3y-2y=2y+32-2y
y=32

2y=x
2*32=x
64=x
x=64

一位億萬老富翁=64 年輕小姐=32

Let old man=3x years old
old man =3x+16 years old now
let his wife = x years old
his wife =x+16 years old now

3x+16/x+16 = 2
3x+16 = 2(x + 16)
3x + 16 = 2x + 32
3x - 2x = 32 - 16
x=16
.'.his wife is 16+16 years old =32 NOW
the old man is 32x2=64 years old now