An article is sold for rupees 642.60 after two successive discount of 15% and 10%. What is the marked price of the article?

₹ 800 ₹ 820 ₹ 840 ₹ 880

₹ 840

Equivalent discount = 15 + 10 - \(\frac{15 × 10}{100}\) = 23.5%                   76.5% = 642.60                   100% = \(\frac{642.60}{76.5}\) × 100 = 840