Question

Calculate the percentage increase in the selling price of a book from 2007 to 2008 if in 2008, the publisher sold 15% more copies than in 2017, and the money collected was 38% higher than in 2007.

Answer 1

The selling price of a book increased by 20% from 2007 to 2008. This was determined by comparing the total revenue increase to the increase in the quantity of books sold.

Step-by-step explanation:

To calculate the percentage increase in the selling price of a book from 2007 to 2008, we must consider both the increase in quantity sold and the increase in total revenue. In 2008, 15% more copies were sold, and the money collected was 38% higher than in 2007. However, these percentages cannot be directly used to find the increase in the selling price, as they relate to different aspects (quantity and revenue).Let's use variables to represent the original selling price and quantity sold. If we denote the original price as P and the original quantity as Q, the total revenue for 2007 is PQ. In 2008, the quantity sold increased to 1.15Q (15% more), and the total revenue collected was 1.38PQ (38% more).The new selling price in 2008 can be found by dividing the new total revenue by the new quantity sold, which gives us 1.38PQ/1.15Q = 1.2P. The percentage increase in selling price is the new price minus the original price, divided by the original price, times 100: (1.2P - P)/P × 100 = 20%.Conclusion: The selling price of the book increased by 20% from 2007 to 2008.