Five years ago, Ram was three times as old as Shyam. Four years from now, Ram will be only twice as old as Shyam. What is the present age of Ram?
32 years
This question is a classic example of an age word problem, which can be solved using linear equations. We are given two conditions relating the ages of Ram and Shyam at different points in time. Our goal is to find Ram's current age.
Let's define variables for their present ages:
Now, we will translate the given conditions into algebraic equations:
We now have a system of two linear equations with two variables:
Let's simplify both equations:
\( R - 5 = 3S - 15 \)
\( R = 3S - 15 + 5 \)
\( R = 3S - 10 \) (Equation 1 Simplified)
\( R + 4 = 2S + 8 \)
\( R = 2S + 8 - 4 \)
\( R = 2S + 4 \) (Equation 2 Simplified)
Now we can use the substitution method or elimination method. Since both simplified equations give an expression for \( R \), we can set them equal to each other:
\( 3S - 10 = 2S + 4 \)
Now, solve for \( S \):
\( 3S - 2S = 4 + 10 \)
\( S = 14 \)
So, Shyam's present age is 14 years.
Now substitute the value of \( S \) (14) into either of the simplified equations to find \( R \). Let's use Equation 2 Simplified (\( R = 2S + 4 \)):
\( R = 2(14) + 4 \)
\( R = 28 + 4 \)
\( R = 32 \)
So, Ram's present age is 32 years.
Let's check if these present ages satisfy the original conditions:
| Ram's Age | Shyam's Age | Check Condition | |
|---|---|---|---|
| Present | 32 | 14 | - |
| 5 years ago | \( 32 - 5 = 27 \) | \( 14 - 5 = 9 \) | Is \( 27 = 3 \times 9 \)? Yes, \( 27 = 27 \). (Condition 1 satisfied) |
| 4 years from now | \( 32 + 4 = 36 \) | \( 14 + 4 = 18 \) | Is \( 36 = 2 \times 18 \)? Yes, \( 36 = 36 \). (Condition 2 satisfied) |
Both conditions are satisfied with Ram's present age as 32 and Shyam's present age as 14. Therefore, the present age of Ram is 32 years.
| Concept | Description | Application in Problem |
|---|---|---|
| Representing Ages | Using variables for unknown quantities (present ages). | Using \( R \) for Ram's present age and \( S \) for Shyam's present age. |
| Ages in Past/Future | Age changes by adding/subtracting years from the present age. | \( R-5 \), \( S-5 \) (5 years ago); \( R+4 \), \( S+4 \) (4 years from now). |
| Forming Equations | Translating word statements into algebraic relationships. | \( R-5 = 3(S-5) \), \( R+4 = 2(S+4) \). |
| Solving System of Equations | Finding the values of variables that satisfy all equations. | Using substitution or elimination to find \( R \) and \( S \). |
| Verification | Checking if the calculated values satisfy the original conditions. | Plugging \( R=32 \) and \( S=14 \) back into the initial statements. |
Age problems are common in algebra and often involve setting up and solving linear equations. Here are some tips:
Understanding how to translate words into mathematical expressions is key to solving age problems effectively.
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