數學的方程式問題

1.The total age of Mr. Chu and his son is 51.Three years ago .How old is his son now?

Let x be his son's present age
Then Mr.Chu ' s present age is 51-x

8 ( x-3) = 51-x-3
8x-24 = 48-x
9x = 72
x = 8

∴ His son ' s presnet age is 8.

p.s. (我認為你護條題目打漏左少少資料 , 應該如下:
The total age of Mr. Chu and his son is 51.Three years ago,he was 8 times as his son.How old is his son now? )

2.The difference between the present ages of Mr. Chan and his son is
32.6 years later, their total age will be 50.Hoe old is Mr. Chan 's son now?

Let x be Mr.Chan 's son present age
Then Mr.Chan present age is 32 x

( x 6 ) ( x 32 6) = 50
2x 44 = 50
2x = 6
x = 3

∴ Mr.Chan ' s son present age is 3

2.
chan's age=x son's age=y
x-y=32
x+y+6+6=50 x+y=38
x=35
y=3 so, son's age is 3.


1.唔該第一題俾多的題示　第一題無法算出答案

2008-04-27 14:39:52 補充：
1.
3 years ago, the total age of Mr. Chu and his son is 45
if the difference between the present ages of Mr. Chan and his son were
29, his son is 8 years old.
let Mr. Chan=x his son=y
x-y=29
x+y=45=3年前既年齡total
x+y+x-y=29+45=74=2x
x=37
y=8

Mr. Chan's son is 8 years old.