Multiple choice

If the current age of a brother exceeds twice the age of his sister by three years, and the age difference between them is 5 years, what will be the ratio of the ages of the brother and the sister five years from now?

  1. 7 : 12

  2. 12 : 7

  3. 9 : 13

  4. 13 : 9

  5. 13 : 10
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let sister be S and brother be B. B = 2S + 3 and B - S = 5. Substituting B = S + 5 into the first equation: S + 5 = 2S + 3, so S = 2 and B = 7. Five years from now, ages are 7+5=12 and 2+5=7. Ratio is 12:7.

AI explanation

Let the sister's current age be s years and the brother's age be b years. The given conditions yield two linear equations: b = 2s + 3 and b - s = 5, which simplifies to b = s + 5. Setting the equations equal gives s + 5 = 2s + 3, which means s = 2, making the brother 7 years old. Five years from now, the brother will be 12 years old and the sister will be 7 years old, making their ratio 12 : 7.

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