If i give my sister 5 dollars, then we will have the same amount of money. if instead she gives me 8 dollars, then i'll have twice as much money as she has. how much money does she
have?

The money my sister have is $34

Step-by-step explanation:

Given as :

The two statements are as

If I give my sister 5 dollars, then we will have the same amount of money  ...A

If instead she gives me 8 dollars, then I'll have twice as much money as she has.      B

Let the money I have = $x

And The money my sister have = $y

Now, From statement A

x - 5 = y + 5

or, x - y = 5 + 5

or, x - y = 10          1

Again, From statement B

2 ×(y - 8) =  (x + 8)

2 y - 16 = x + 8  

2 y - x = 24         2

Now, solving Eq 1 and 2

Put the value of x from eq 1 into eq 2

2 y - (y + 10) = 24

Or, 2 y - y = 24 + 10

Or, y = 34

So, The money my sister have = y = $34

Put the value of y into eq 1

so, x - 34 = 10  

I.e x = 10 + 34

∴ x = 44

So, The money I have = x = $44

Hence, The money my sister have is $34 Answer

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step-by-step explanation: