A ready-made garments shop in Delhi allows 20 percent discount on its garments and still makes a profit of 20 percent. Find the marked price of a dress which is bought by the shopkeeper for ₹ 400.

At 12% discount, the selling price of a pen is ₹ 13.20. Find its marked price. Also find the new selling price of the pen, if it is sold at 5% discount.

Thirty articles are bought at ₹ 450 each. If one-third of these articles are sold at 6% loss; at what price must each of the remaining articles be sold in order to make a profit of 10% on the whole ?

Find the single discount (as percent) equivalent to successive discounts of :

(i) 80% and 80%

(ii) 60% and 60%

(iii) 60% and 80%