SOLUTION: How to set up this equation? Cathy is 16 years younger than Mary. In 5 years, Mary will be as twice as old as Cathy. Find their ages now.

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Question 928023: How to set up this equation? Cathy is 16 years younger than Mary. In 5 years, Mary will be as twice as old as Cathy. Find their ages now.
Found 2 solutions by TimothyLamb, MathTherapy:
Answer by TimothyLamb(4379)   (Show Source): You can put this solution on YOUR website!
x = cathy age now
y = mary age now
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x = y - 16
y + 5 = 2x
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put the system of linear equations into standard form
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x - y = -16
2x - y = 5
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copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = cathy age now = 21
y = mary age now = 37
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Solve and graph linear equations:
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Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

How to set up this equation? Cathy is 16 years younger than Mary. In 5 years, Mary will be as twice as old as Cathy. Find their ages now.
Let Cathy's present age, be C

Then Mary's present age = C + 16

We then have: C + 16 + 5 = 2(C + 5)

C + 21 = 2C + 10

C - 2C = 10 - 21

- C = - 11

C, or Cathy's present age = , or 

Mary's present age: 11 + 16, or 

You can do the check!!  

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