What is single discount equivalent to two successive discounts of 15% and 20%?

If in a sale, the discount given on a saree is equal to one-fourth of the marked price and the loss due to this discount is 15%, then the ratio of the cost price to the selling price is-

A bookseller allowed 10 % discount on printed price. He gets 30 % commission from publisher. His profit in percent will be 

A shopkeeper allows a discount of 10% on the marked price of an item but charges a sales tax of 8% on the discounted price. If the customer pays ₹ 3,402 as the price including the sales tax, then the marked price is 

Raghav went to a shopping mall to purchase clothes. He had two coupons with him, but only one can be used on a single day. Using the first coupon, a total discount of 30% could be obtained on the total amount. Using the second coupon, he will get 80% off on the price of the costliest shirt if he buys at least 3 shirts. What is the price at which Raghav can purchase 3 shirts at a minimum price if the prices of the three shirts are Rs.1,250, Rs.1,540 and Rs.1,375?

At a clearance sale, a shopkeeper gives 45% discount. If a customer paid ₹330 during the sale, then what is the marked price of that shirt?