SOLUTION: Please help me to solve this.: In 2 yrs Jack will be double his sister Jen's age. The sum of Jacks age and 3 times Jen's age equals 66. What is Jen's age? What is the formula to

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Question 188991: Please help me to solve this.: In 2 yrs Jack will be double his sister Jen's age. The sum of Jacks age and 3 times Jen's age equals 66.
What is Jen's age? What is the formula to find this out and what is the answer?
I have tried X+3Y=66; then X+y= 66/3; X+Y=22; then coming up with Jen's age as 10, but somehow this doesn't seem right. I hope you can help.
Found 2 solutions by stanbon, jonvaliente:
Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website!
In 2 yrs Jack will be double his sister Jen's age.
The sum of Jacks age and 3 times Jen's age equals 66.
What is Jen's age? What is the formula to find this out and what is the answer?
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NOW DATA:
Let Jack be k years old.
Let Jen be j years old.
Equation: k + 3j = 66
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In 2 yrs DATA:
Equation: k+2 = 2(j+2)
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Rearrange the equations:
k + 3j = 66
k - 2j = 2
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Subtract the 2nd equation from the 1st to solve for "J":
5j = 64
j = 12.8 years old (Jen's age now)
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Cheers,
Stan H.

Answer by jonvaliente(64) (Show Source):
You can put this solution on YOUR website!
Let x = jack's age
Let y = Jen's age
In two years, Jack will be double Jen's age:

The sum of Jack's age and 3 times Jen's age is 66:
(2)
Simplifying the first equation, we get:
or...
(1)
Subtracting equation (1) from (2) we get:

-
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Dividing both sides by 5, we get:

Solving for Jack's age, using equation (2), we get:

Therefore:
Jack is 27.6 years old while Jen is 12.8 years old