Question 607061: please help me solve this problem.
Eva is 2 years older than Julienne. The sum of their ages is 20. Find their present ages.
Answer by sophxmai(62)   (Show Source):
You can put this solution on YOUR website! Eva is 2 years older than Julienne. The sum of their ages is 20. Find their present ages.
Let:
Eva's age = x
Julienne's age = y
x+y=20 <--the sum of their ages is 20
x-2=y <--Eva is 2 years older than Julienne
You can solve this system by either adding/subtracting or substituting.
Adding/Subtracting:
x+y=20
x-2=y
Rearrange the 2nd equation
x-2=y becomes x-y=2
So now we have
x+y=20
x-y=2
Now add the equations, you will get
2x=22
Now solve...
2x=22
x=11
Now that you have x, plug it into one of the equations to solve for y
x-y=2
11-y=2
11-2=y
9=y
Since x=11 and y=9
Eva's age is 11 and Julienne's age is 9
Substituting:
x+y=20
x-2=y
Since the 2nd equation is already arranged in a way that a variable = something... substitute it into the 1st equation.
x+y=20
x+(x-2)=20
x+x-2=20
2x-2=20
2x=22
x=11
Now that you have 11, plug x into your 2nd equation
x-2=y
11-2=y
9=y
Since x=11 and y=9
Eva's age is 11 and Julienne's age is 9
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