Children's Bookstore: All books are sold at a 30% discount.

Xinhua Bookstore: Buy four books and get one free.

In the sixth grade, I want to buy 20 interesting math books. Which bookstore is cheaper to buy?

Solution: Suppose a book is X yuan.

Children's Bookstore: 70%x×20= 14x

Xinhua Bookstore: 15x+2x= 17x

A: It's cheaper to buy it in a children's bookstore.

(2) A down jacket is marked with 25% of the purchase price. Later, because the weather turned warmer, it was sold at a price of 75%. After this down jacket was sold, did it make a profit or a loss?

Solution: Let the original price be X yuan.

( 1+25%)x×75%

= 1.25x×75%

=0.9375x

Yes, I did.