Question 1149530
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The statement of the problem is faulty; it says now Antonette is older and 6 years ago her sister was older.<br>
I will ignore that and solve the problem as it was probably intended -- with Antonette older.<br>
Using formal algebra... which I will assume is what you are learning to do by asking this question....<br>
Let the sister's age be x
Then Antonette's age is x+3<br>
Then 6 years ago the sister's age was x-6, and Antonette's age was (x+3)-6 = x-3.<br>
Then, since 6 years ago Antonette was 4 times as old as her sister,<br>
{{{x-3 = 4(x-6)}}}
{{{x-3 = 4x-24}}}
{{{21 = 3x}}}
{{{x = 7}}}<br>
ANSWER: Antonette's age is x+3 = 10 years<br>
CHECK: 6 years ago, Antonette was 10-6 = 4 years old and her sister was 7-6 = 1 year old; Antonette was 4 times as old as her sister.<br>
Note that, if a formal algebraic solution is not required, the question can be answered quickly with a little logical reasoning and simple arithmetic.<br>
If the difference between their ages is 3 years, then when Antonette was 4 times as old as her sister, their ages had to be 4 and 1.<br>
And since that was 6 years ago, their ages now are 10 and 7.<br>
While knowing how to solve problems like this with formal algebra is important, solving them using logical reasoning is also good mental exercise.<br>