SOLUTION: Alex is 3 years older than Sophia. In 9 years the sum of their ages will be 55. How old is Alex now?

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Question 1154724: Alex is 3 years older than Sophia. In 9 years the sum of their ages will be 55. How old is Alex now?

Found 3 solutions by Alan3354, jim_thompson5910, MathTherapy:
Answer by Alan3354(69443)   (Show Source):
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Alex is 3 years older than Sophia. In 9 years the sum of their ages will be 55. How old is Alex now?
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Hint: The sum of their ages now is 55 - 18 = 37.

Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website!

A = Alex's current age
S = Sophia's current age

Right now, Alex is 3 years older than Sophia.
We add 3 years to Sophia's age (S) to get Alex's age (A)
A = S+3
This equation will hold true for past and future ages as well.

Let's fast-forward into the future.
A+9 = Alex's age 9 years from now
S+9 = Sophia's age 9 years from now
Those two expressions sum to
(A+9)+(S+9) = A+S+18
and we are told this is equal to 55
A+S+18 = 55

Plug in A = S+3 and solve for S

A+S+18 = 55
S+3+S+18 = 55 ... wherever you see an 'A", replace with 'S+3'
2S+21 = 55
2S+21-21 = 55-21 .... subtract 21 from both sides
2S = 34
2S/2 = 34/2 ... divide both sides by 2
S = 17
Currently, Sophia is 17 years old

Use her current age to find Alex's current age
A = S+3
A = 17+3
A = 20

Answer: Alex is currently 20 years old

Answer by MathTherapy(10552)   (Show Source):
You can put this solution on YOUR website!

Alex is 3 years older than Sophia. In 9 years the sum of their ages will be 55. How old is Alex now?

Let Alex' be A
Then Sophia's is: A - 3
We then get: A + A - 3 + 2(9) = 55
2A - 3 + 18 = 55
2A = 40
A, or Alex is: