Explanation:

- Akshay has 30 articles, each with the same cost price.

- He marks each article 30% above its cost price.

- Sold 15 articles at a 20% discount, and 15 articles at a 10% discount.

- His total profit is Rs 630.

Let's calculate:

1. Let the cost price of each article be Rs x.

2. Marked price of each article = 130% of x = 1.3x.

15 articles, 20% discount:

- Selling price = 80% of 1.3x = 1.04x per article.

- Total selling price for these 15 = 15 × 1.04x = 15.6x.

15 articles, 10% discount:

- Selling price = 90% of 1.3x = 1.17x per article.

- Total selling price for these 15 = 15 × 1.17x = 17.55x.

Total selling price = 15.6x + 17.55x = 33.15x.

Total cost price = 30x.

Profit = Selling price - Cost price = 33.15x - 30x = 3.15x = Rs 630.

Solving for x:

- 3.15x = 630

- x = 630 / 3.15 = 200

- Cost price per article = Rs 200.

- Answer: Option 4 - Rs 200