Question 1172651:  The sum of the ages of Gerardo and Alexis is 104 years. 12 years ago, Gerardo's age was 3 times Alexis's age. How old is Gerardo now? 
 
 Found 5 solutions by  ewatrrr, greenestamps, Solver92311, ikleyn, MathTherapy: Answer by ewatrrr(24785)      (Show Source): 
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Hi   
Let x represent Alexis' age ..12 years ago 
and 3x  Gerardo's age ..12 years ago 
12 years ago... 104 - 12 = 92 
x + 3x = 92 
4x = 92 
x = 23  Alexis' age 12 years ago 
23+12 = 35 Alexis' age NOW 
35 + C(now) = 104 
C(now)= 69  Gerardo's age NOW 
CHECKING our answer*** 
35 + 69 = 104 
Wish You the Best in your Studies.  
 Answer by greenestamps(13215)      (Show Source): 
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I suspect the interpretation of the given information by the other tutor is not correct.
  
I think the information is that Gerardo's age 12 years ago was 3 times Alexis's age 12 years ago -- not 3 times Alexis's current age....
  
12 years ago, the sum of their ages was 104-2(12) = 80.
  
At that time, Gerardo was 3 times as old as Alexis.  Any number of different methods can be used to determine that their ages 12 years ago were 60 and 20.
  
So Gerardo's age now is 60+12 = 72.
  
 
 Answer by Solver92311(821)      (Show Source):  Answer by ikleyn(52903)      (Show Source): 
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The sum of the ages of Gerardo and Alexis is 104 years. 12 years ago, Gerardo's age was 3 times Alexis's age.  
How old is Gerardo now? 
~~~~~~~~~~~~~~~~~
 
 
 
Let x be the Alexis' age.
Then the Gerardo age is  (104-x) years.
12 years ago
    Alexis age was (x-12) years,
    Gerardo's age was  (104-x-12) = (92-x),
        and the equation states
            92 - x = 3*(x-12)
Simplify it
    92 - x = 3x - 36
    92 + 36 = 3x + x
      128   = 4x
        x   = 128/4 = 32. 
ANSWER.  Gerardo's age is 104 - 32 = 72 years.
 
Solved.
 
 
 
 Answer by MathTherapy(10557)      (Show Source): 
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The sum of the ages of Gerardo and Alexis is 104 years. 12 years ago, Gerardo's age was 3 times Alexis's age. How old is Gerardo now? 
Doesn't make sense, at all, to name a variable for one of the 2 people's ages 12 years ago 
Having said that, let's make Gerardo's age, G 
Then Alexis' is: 104 - G 
We the get: G - 12 = 3(104 - G - 12) 
G - 12 = 3(92 - G) 
G - 12 = 276 - 3G 
G + 3G = 276 + 12 
4G = 288 
Gerardo, or    
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