SOLUTION: Yoshi +12 years = her sister's age. 6 years from now the sum of their ages will equal 32. What is Yoshi's present age?

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Question 315423: Yoshi +12 years = her sister's age.
6 years from now the sum of their ages will equal 32.
What is Yoshi's present age?

Answer by moshiz08(60) About Me  (Show Source):
You can put this solution on YOUR website!
We have the first equation Y+%2B+12+=+S (where Y = yoshi's age, S = her sister's age)
For the second equation (6 years from now the sum of their ages will equal 32): six years from now we know that Yoshi's age will be Y+6. Her sister's age will be S+6. Thus the equation reads:
%28Y%2B6%29+%2B+%28S%2B6%29+=+32. This is the same as combining like terms to give Y+%2B+S+%2B+12+=+32 or subtracting 12 from both sides to give Y+%2B+S+=+20.
But we know from the first equation that S+=+Y+%2B+12. Substitute this into Y+%2B+S+=+20 to give Y+%2B+%28Y%2B12%29+=+20. Then combining like terms gives 2Y+%2B+12+=+20. Subtracting 12 from both sides gives 2Y+=+8. Dividing by 2 yields Y+=+4.
Now we check. If yoshi is 4 years old, then his sister is 4+12 = 16 years old.
In six years, yoshi will be 10. His sister will be 22. The sum of their ages (10 + 22) gives us 32, so the answer yoshi is 4 works.