math question a bookstore announces a promotion valid for the same purchase as follows: buy a book and get 10% off the total purchase! buy two books and get 20% off your total purchase! buy three or more books and get 30% off your total purchase! Marcelo wanted to buy three books that cost 20.00 each without discount but he decided to buy two books in one day and another purchase with the third book the next day. If he had bought the three books at once he would have saved the following amount.

Let's calculate the total cost of buying three books separately and then compare it to the cost if Marcelo had bought all three books at once. The cost of one book is $20.00. Buying two books on the first day: Cost of the first book: $20.00 Cost of the second book: $20.00 Total cost for two books on the first day: $20.00 + $20.00 = $40.00 - $8(20% off) = $32 Buying the third book on the next day: Cost of the third book: $20.00 Total cost for the third book on the next day: $20.00 - 2(10% off) = $18 Now, let's calculate the total cost if Marcelo had bought all three books at once: Buying all three books at once: Cost of the first book: $20.00 Cost of the second book: $20.00 Cost of the third book: $20.00 Total cost for all three books at once: $20.00 + $20.00 + $20.00 = $60.00 - $18 (30% off) = $42 Now, let's calculate the savings if Marcelo had bought all three books at once compared to buying two books on the first day and the third book on the next day: Savings = Total cost of buying separately − Total cost of buying all at once Savings = $50 - $42 = $8 So, Marcelo would have saved $8 if he had bought all three books at once.