SOLUTION: i need help!! Two teenagers, Simon and Joe take on weekend $85 and $70 respectively. During this break, Joe spends $5 more than Simon. At the end of the holiday Simon has twice as

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Question 23945: i need help!!
Two teenagers, Simon and Joe take on weekend $85 and $70 respectively. During this break, Joe spends $5 more than Simon. At the end of the holiday Simon has twice as much money left as Joe. Calculate how much money each lad spent.
Answer by vikved(3) About Me  (Show Source):
You can put this solution on YOUR website!
The answer to this question involves using two variables. Let us review the question again and see what is given :
Simon has $85 to start off with. Joe has $70 to start off.
First variable : During the weekend, let us assume that Joe spent x dollars. Therefore, Simon spent (x-5) dollars.
Second variable : Joe is left with y dollars. Simon is left with twice as much money, or in other words, 2y dollars.
Let us now represent the equations. Consider what Joe had to start with, how much he spent, and how much he is now left with :
JOE : $70 to start off; he spent x dollars; he is now left with y dollars.
70+=+x%2By
SIMON : $85 to start off; he spent (x-5) dollars; he is now left with 2y dollars.
85+=+%28x-5%29%2B2y
We now have 2 equations and two unknowns. We can solve these by simulatenous equation methods. Simplifying the equations, we get :
x%2By+=+70
x%2B2y+=+90
Solving this we get y = 20.
Thus, Joe is left with $20. Simon would be left with 2y = $40.
Joe spent 70-y = $50.
Simon spent 85-2y = 85-40 = $45.