The cost of 13 pens is `Rs 58 1/2`. Find the cost of each pen.

Answer

To find the cost of each pen when the cost of 13 pens is given as Rs 58 1/2, we can follow these steps:

### Step 1: Convert the mixed fraction to an improper fraction
The cost of 13 pens is Rs 58 1/2. We can convert this mixed number into an improper fraction.

- The whole number part is 58.
- The fractional part is 1/2.

To convert it:
1. Multiply the whole number by the denominator: \( 58 \times 2 = 116 \).
2. Add the numerator to this product: \( 116 + 1 = 117 \).
3. Place this sum over the original denominator: \( \frac{117}{2} \).

So, Rs 58 1/2 can be written as \( \frac{117}{2} \).

### Step 2: Set up the equation for the cost of each pen
Let the cost of each pen be \( x \). Since the cost of 13 pens is \( \frac{117}{2} \), we can write the equation:
\[ 13x = \frac{117}{2} \]

### Step 3: Solve for \( x \)
To find \( x \), we need to isolate it on one side of the equation. We can do this by dividing both sides by 13:
\[ x = \frac{117}{2} \div 13 \]

This can be rewritten as:
\[ x = \frac{117}{2} \times \frac{1}{13} \]

### Step 4: Simplify the expression
Now we can simplify:
\[ x = \frac{117 \times 1}{2 \times 13} = \frac{117}{26} \]

Next, we can simplify \( \frac{117}{26} \):
- Divide both the numerator and the denominator by their greatest common divisor (GCD), which is 13:
\[ x = \frac{117 \div 13}{26 \div 13} = \frac{9}{2} \]

### Conclusion
The cost of each pen is \( \frac{9}{2} \) or Rs 4.50.

---