數學題....解方程

1) 設你有A元
A+(1-40%)A=720
A+0.6A=720
1.6A=720
A=450
所以你有450元~

2) 1 X (16-K)+2K=30
16-K+2K=30
K=14

1.設姊姊有y元, 我比姊姊少40%, 所以我有(1-40%)y元.

姊姊和我共有720元, 所以,
y + (1-40%)y = 720
y + 0.6y = 720
1.6y = 720
y = 450

因此, 姊姊有450元, 而我則有 720 - 450 = 270(元)

2. 1x(16-K)+2K=30
16 - K + 2K = 30
16 + K = 30
K = 30 - 16
K = 14

設你有p元
p+(1-40)p=720
p+0.6p=720
1.6p=720
p=450
So你有450元~p
1 X (16-K)+2K=30
16-K+2K=30
K=14

1.)設我有$x.
x+(60%)x=720
x+0.6x=720
1.6x=720
x=450
2.)
1x(16-k)+2k=30
16-k+2k=30
16+k=30
k=14

1.設姊姊有x元, 我比姊姊少40%, 所以我有(1-40%)x元.

姊姊和我共有720元, 所以,
x + (1-40%)x = 720
x + 0.6x = 720
1.6x = 720
x = 450

因此, 姊姊有450元, 而我則有 720 - 450 = 270(元)

2. 1乘(16-K)+2K=30
(16 - K) + 2K = 30
16 - K + 2K = 30
16 + K = 30
K = 30 - 16
K = 14

l1.姊姊和我共有720元,我比姊姊少40%,我有多少元?

et x be the money I have, and y be the money my sister have

x+y=720------------------------1
x(1+0.4)=y----------------------2

sub 2 into 1
1.4x+x=720
2.4x=720
x=300

sub x=300 into 1
300+y=720
y=420

ThereforeI have $300, my sister have $420



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2.1乘(16-K)+2K=30

1*(16-K)+2K=30
16-K+2K=30
-K+2K=14
K=14

1) 我有270

2) 1 x (16-K) + 2K = 30
=> 16 - K + 2K = 30
=> K = 30 - 16
=> K = 14