數學(都幾難)麻煩各位幫下手

no1:
let say x = girl; y = mother
x+y = 62 ( according to the sum of their ages )
x = 62-y
then
x =1/2(y) +2 ( girl is 2 yrs older than half of mother's age)
so
62-y = 1/2(y) +2
60 -y = 1/2 (y)
120-2y = y
120=3y
y=40
so x = 62-40
x =22

The other two questions use the same logic.
You can let sth to be x and y .. .then the rest are easy..
Try to do it yourself.
It's easy.
In fact, mathematics is a easy subject.
You know why? Because maths has only one and one answer.
Once u get older, u will find many things have many ways to do with many answers...
That will be much more difficult.

1)
Let the age of the mother be y years
Then the age of the girl is (y/2+2)years
y+(y/2+2)=62
2y+y+4=124
3y=120
y=40
The age of the mother is 40 years, then the age of the girl is 40/2+2=22 years.

2)
Let the total amount of the money be $y
y/8-y/10=30
5y-4y=1200
y=1200
Therefore the total amount of money is $1200.

3)
Let the money of Paul be $y
Then the money of Peter is $(y+9)
The money of Philip is $(y+9)/3
y+(y+9)+(y+9)/3=67
3y+3y+27+y+9=201
7y+36=201
7y=165
y=165/7
Therefore the money of Paul is $165/7, the money of Peter is $165/7+9=$228/7, the money of Philip is $(228/7)/3=$76/7

1. A girl’s age is 2 years more than 1/2 of her mother’s age.If the sum of their ages is 62,find their ages.
let the age of the girl be x
then the age of her mother is 62-x
x-2=(62-x)/2
2x-4=62-x
3x=66
x=22
62-x=40
so the age of the girl is 22 , and her mother’s age is 40


2.A sum of money is to be evenly shared among 10 persons.However,two of them are absent,so each of the 8 attenddds gets $30 more.Find the total amount of money.
let the total amount of money be x
x/10=(x/8) -30
x/10=(x-240)/8
8x=10x-2400
2x=2400
x=1200
so the total amount of money is $1200


3.Peter has $9 more than Paul,and Philip’s is 1/3 of Peter’s.How much money does
each of them have if they have a total of $67?
let x be the amount of money of Peter
then Paul has $(x-9)
Philip has $(x/3)
x+(x-9)+(x/3)=67
3x+3x-27+x=201
7x=228
x=228/7
Peter has $ 228/7
Paul has $165/7
Philip has $76/7

第一及三題亂了碼﹐ 不太清楚題目應該是怎樣﹐以下為第二題的解答﹕

If sum of money = x

x/10 + 30 = x/8
8(x+300) = 10x
8x + 2400 = 10x
10x - 8 x = 2400
2x = 2400
x = 1200

上面的“/”是為分數線