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.

Both of them are correct. Oscar took 30% out of 28.50 which equaled 8.55. He then subtracted the discount from the original price which equaled 19.95. After that he found 10% of 20.00 (an estimate) which was 2. Finally he subtracted 2 from 19.95 making an estimate amount of $21.95. Kim, instead of finding the price of the discount, found the amount she would have to pay after the discount. She figured out that 70% of the original price would be the price after the discount. So she then took 70% of 28.50, which equaled 19.95. She then took 110% of 19.25, which equaled 21.95, and found the answer. Even though Oscar and Kim did the math in different ways they still got the same correct answer.