Question 1154724
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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 <font color=red size=4>20 years old</font>

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