Present ages of Sai and Satheesh are in the ratio of 5 : 4 respectively. Three years hence, the ratio of their ages will become 11 : 9 respectively. What is Satheesh’s present age in years?
24
This problem involves finding the present ages of two individuals, Sai and Satheesh, given their current age ratio and their age ratio after a certain number of years. We can use algebraic methods to solve this type of age problem.
Let's represent the present ages of Sai and Satheesh using a variable based on their current ratio.
Now, let's consider their ages after three years:
The problem states that the ratio of their ages after three years will be 11 : 9. We can write this as an equation:
$\frac{\text{Sai's age after 3 years}}{\text{Satheesh's age after 3 years}} = \frac{11}{9}$
Substituting the expressions for their ages:
$\frac{5x + 3}{4x + 3} = \frac{11}{9}$
Now we need to solve this equation for $x$. We can do this by cross-multiplication:
$9 \times (5x + 3) = 11 \times (4x + 3)$
Distribute the numbers on both sides:
$9 \times 5x + 9 \times 3 = 11 \times 4x + 11 \times 3$
$45x + 27 = 44x + 33$
Now, we need to isolate the term with $x$. Subtract $44x$ from both sides:
$45x - 44x + 27 = 33$
$x + 27 = 33$
Subtract 27 from both sides to find the value of $x$:
$x = 33 - 27$
$x = 6$
We defined Satheesh's present age as $4x$ years. Now that we have the value of $x$, we can calculate Satheesh's age:
Satheesh's present age $= 4x = 4 \times 6 = 24$ years.
Let's also check Sai's present age: $5x = 5 \times 6 = 30$ years.
After 3 years, Sai's age would be $30 + 3 = 33$ years, and Satheesh's age would be $24 + 3 = 27$ years. The ratio would be $33 : 27$. Dividing both numbers by 3, we get $11 : 9$, which matches the information given in the problem. This confirms our value for $x$ is correct.
| Person | Present Age (in terms of x) | Present Age (in years) |
|---|---|---|
| Sai | $5x$ | $5 \times 6 = 30$ |
| Satheesh | $4x$ | $4 \times 6 = 24$ |
Therefore, Satheesh's present age is 24 years.
| Step | Description | Calculation / Expression |
|---|---|---|
| 1 | Define present ages using ratio | Sai: $5x$, Satheesh: $4x$ |
| 2 | Define ages after 3 years | Sai: $5x + 3$, Satheesh: $4x + 3$ |
| 3 | Set up equation from future ratio | $\frac{5x + 3}{4x + 3} = \frac{11}{9}$ |
| 4 | Solve for x | $9(5x + 3) = 11(4x + 3) \implies 45x + 27 = 44x + 33 \implies x = 6$ |
| 5 | Calculate Satheesh's present age | $4x = 4 \times 6 = 24$ |
Ratio problems often involve comparing quantities. When dealing with ages, ratios change over time. If the ratio of two ages is $a:b$, we can represent the ages as $ax$ and $bx$, where $x$ is a common factor. When time passes (say, $t$ years), their ages become $ax + t$ and $bx + t$. The new ratio can then be used to form an equation to solve for $x$. This common factor $x$ is crucial because it allows us to scale the ratio to the actual values of the ages.
Key steps in solving age ratio problems:
Always double-check your answer by plugging the calculated ages back into the conditions given in the problem.
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