A shopkeeper buys 20 pens at ₹15 each and another 30 pens at ₹10 each. He mixes all the pens and sells them at ₹14 each. What is the profit or loss per pen he makes on an average?​

Correct option is D

Given:
- 20 pens at ₹15 each
- 30 pens at ₹10 each
- Selling price of each pen = ₹14
- We need to find the profit or loss per pen on average.

 Formula Used:
- Total cost = (Cost price of first batch × Quantity) + (Cost price of second batch × Quantity)
- Total selling price = Selling price × Total quantity
- Profit or Loss = Total selling price - Total cost
- Profit or Loss per pen = (Profit or Loss) / Total quantity

Solution:

- Total cost for first batch = 20 × ₹15 = ₹300
- Total cost for second batch = 30 × ₹10 = ₹300
- Total cost = ₹300 + ₹300 = ₹600

- Total selling price = 50 × ₹14 = ₹700

- Profit = ₹700 - ₹600 = ₹100

- Profit per pen = ₹100 / 50 = ₹2

Therefore, the profit per pen is ₹2.