1元1次方程

Mary 有 x咁多錢

Peter 有 3.5x

Ken 有 4.5x

所以

3.5x+4.5x+x = 4770

9x = 4770

x= 530

Ken 有 4.5*530 = $2385

PETER:MARY =3.5: 1
MARY:KEN = 1:4.5
------------------------------------------------
PETER:MARY:KEN =7: 2 : 9

LET PETER=7K,MARY=2K,KEN=9K

THEN,7K+2K+9K=$4770
18K=$4770
K=265

SO, KEN =9($265)
=$2385

設ken有$y,則mary有$y/4.5,peter有$3.5y/4.5
y+y/4.5+3.5y/4.5=4770
9y+2y+7y=4770
18y=4770
y=256
所以ken有$256

let x be the $ of Mary:
4.5x be the $ of Ken
3.5xbe the $ of peter
x+4.5x+3.5x=4770
9x=4770
x=530
Ken's money:4.5 X 530
=2385
ken has $2385

Let $x be the amount of dollar of Marry's
The formula should be like this: 4700=3.5x+4.5x+x
But the ans need to calculate by yourself