Alison is 26 years younger than her father. Her father's age will be 3 times her age in 4 years. How old is Alison?



Answer :

To solve this problem, let's define the variables and use the given information in a step-by-step manner:

1. Define variables:
- Let "A" represent Alison's current age.
- Let "F" represent her father's current age.

2. According to the problem:
- Alison is 26 years younger than her father. Therefore, we can state:
[tex]\[ F = A + 26 \][/tex]

3. Future ages in 4 years:
- In 4 years, Alison's age will be [tex]\(A + 4\)[/tex].
- In 4 years, her father's age will be [tex]\(F + 4\)[/tex].

4. Condition given in the problem:
- Her father's age in 4 years will be 3 times Alison's age in 4 years. Mathematically, this can be expressed as:
[tex]\[ F + 4 = 3 \times (A + 4) \][/tex]

5. Substitute the expression for [tex]\(F\)[/tex] from step 2:
- Substitute [tex]\(F = A + 26\)[/tex] into the equation [tex]\(F + 4 = 3 \times (A + 4)\)[/tex]:
[tex]\[ (A + 26) + 4 = 3 \times (A + 4) \][/tex]

6. Simplify and solve for [tex]\(A\)[/tex]:
[tex]\[ A + 26 + 4 = 3(A + 4) \][/tex]
[tex]\[ A + 30 = 3A + 12 \][/tex]
- Bring all terms involving [tex]\(A\)[/tex] to one side:
[tex]\[ A + 30 - 12 = 3A \][/tex]
[tex]\[ 18 = 2A \][/tex]
- Divide both sides by 2 to solve for [tex]\(A\)[/tex]:
[tex]\[ A = 9 \][/tex]

Therefore, Alison is currently 9 years old.

7. Verification:
- If Alison is 9 years old, her father's current age, [tex]\(F\)[/tex], is:
[tex]\[ F = A + 26 = 9 + 26 = 35 \][/tex]
- In 4 years, Alison's age will be [tex]\(9 + 4 = 13\)[/tex] and her father's age will be [tex]\(35 + 4 = 39\)[/tex].
- Checking the condition: Is 39 three times 13?
[tex]\[ 39 = 3 \times 13 \][/tex]
- Yes, it is correct.

Thus, the solution is verified, and Alison is 9 years old.