Five pens cost Rs 115. How much will 7 pens cost ?

Answer

To solve the problem of how much 7 pens will cost when 5 pens cost Rs 115, we can follow these steps:

### Step-by-Step Solution:

1. **Find the cost of one pen:**
- We know that the cost of 5 pens is Rs 115.
- Let the cost of one pen be \( x \).
- Therefore, the equation can be set up as:
\[ 5x = 115 \]

2. **Solve for \( x \):**
- To find the cost of one pen, we need to divide both sides of the equation by 5:
\[ x = \frac{115}{5} \]
- Performing the division:
\[ x = 23 \]
- So, the cost of one pen is Rs 23.

3. **Calculate the cost of 7 pens:**
- Now that we know the cost of one pen, we can find the cost of 7 pens by multiplying the cost of one pen by 7:
\[ \text{Cost of 7 pens} = 7 \times x = 7 \times 23 \]
- Performing the multiplication:
\[ 7 \times 23 = 161 \]
- Therefore, the cost of 7 pens is Rs 161.

### Final Answer:
The cost of 7 pens is Rs 161.

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