Question

Oscar and Kim have $22.00 each to spend at a book fair, where all students receive a 30%; discount. They both want to purchase a copy of the same book, which normally sells for $28.50 plus 10% sales tax. To check if he has enough to purchase the book, Oscar takes 30% of $28.50 and subtracts that amount from the normal price. He takes 10% of the discounted selling price and adds it back to find the purchase amount. Kim takes 70% of the normal purchase price and then computes 110% of the reduced price. Is Oscar correct? Is Kim correct? Do they have enough money to purchase the book? Explain your answer using complete sentences. Be sure to show your calculations for determining the final cost of the book for each student. (10 points)

Answer 1

Oscar is correct.

When you calculate discounts & sale price, you do not add them. With sales tax, you only tax what you pay for.

Find the discount price

28.50 • 0.3 = 8.55

Subtract

28.50 - 8.55 = 19.95

Find the sales tax

19.95 • 0.1 = 1.99

Add sales tax

19.95 + 1.99 = 21.94

Oscar paid $21.94

Since Kim wants the same book, she is going to pay the same price.