Given: Selling price = Rs. 4900 Loss % = 12.5% Formula used: Profit % = [(SP – CP)/CP] × 100 Loss % = [(CP – SP)/CP] × 100 Calculations: Let the cost price of the book be Rs. x and the new selling price be Rs. y ⇒ [(x – 4900)/x] × 100 = 12.5 ⇒ (x – 4900)/x = 1/8 ⇒ 8x – 4900 × 8 = x ⇒ 7x = 4900 × 8 ⇒ x = 700 × 8 ⇒ x = Rs. 5600 To earn a profit of 25% ⇒ [(y – 5600)/5600] × 100 = 25 ⇒ (y – 5600)/5600 = 1/4 ⇒ 4y – 5600 × 4 = 5600 ⇒ 4y = 5600 + 5600 × 4 ⇒ 4y = 5 × 5600 ⇒ y = 5 × 1400 ⇒ y = Rs. 7000 ∴ The book should be sold for Rs. 7000 to earn a profit of 25%