Meenu is 38 years old. Her daughter is 8 years old. In how many years will Meenu be double her daughter's age?
22
This problem is a classic example of an age-based word problem that can be solved using linear equations. We are given the current ages of Meenu and her daughter and asked to find the number of years after which Meenu's age will be exactly double her daughter's age.
Let's define the current ages:
We want to find the number of years from now when Meenu's age will be double her daughter's age. Let 'x' be the number of years we are looking for.
After 'x' years:
The problem states that after 'x' years, Meenu's age will be double her daughter's age. We can write this as an equation:
\(\text{Meenu's age after x years} = 2 \times (\text{Daughter's age after x years})\)
\(38 + x = 2 \times (8 + x)\)
Now, we need to solve the linear equation for 'x':
\(38 + x = 2(8 + x)\)
First, distribute the 2 on the right side of the equation:
\(38 + x = 16 + 2x\)
Next, we want to isolate 'x' on one side of the equation. We can subtract 'x' from both sides:
\(38 + x - x = 16 + 2x - x\)
\(38 = 16 + x\)
Now, subtract 16 from both sides to find the value of 'x':
\(38 - 16 = 16 + x - 16\)
\(22 = x\)
So, after 22 years, Meenu will be double her daughter's age.
Let's check if this answer is correct by calculating their ages after 22 years:
Is Meenu's age double her daughter's age? \(60 = 2 \times 30\). Yes, \(60 = 60\). The condition is satisfied.
Therefore, in 22 years, Meenu will be double her daughter's age.
| Age | Current | After 22 Years |
|---|---|---|
| Meenu | 38 | 38 + 22 = 60 |
| Daughter | 8 | 8 + 22 = 30 |
The number of years required is 22.
| Concept | Explanation | How it applies here |
|---|---|---|
| Representing Unknowns | Use variables (like \(x\)) for the quantities you need to find (e.g., number of years, age). | We used \(x\) for the number of years. |
| Expressing Future/Past Ages | To find age after \(y\) years, add \(y\) to current age. To find age \(y\) years ago, subtract \(y\). | We used \(38 + x\) and \(8 + x\) for future ages. |
| Forming Equations | Translate the relationships given in the problem into algebraic equations. | "Meenu's age will be double her daughter's age" translates to \(38 + x = 2(8 + x)\). |
| Solving Linear Equations | Use algebraic techniques (distribute, combine like terms, isolate the variable) to find the value of the unknown. | We solved \(38 + x = 16 + 2x\) to get \(x = 22\). |
Age problems often involve relationships between the ages of two or more people at different points in time. Common types include:
The key to solving these problems is carefully defining variables and translating the given information into algebraic equations.
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