word problem in algebra

Question

suppose you write a book. The printer charges $4 per book to print it, and you spend $5500 on advertising. you sell the book for $15 a copy. How many copies must you sell to break even (total cost equals income from sales0? and What is your income (or costs) for that many copies?

Answer 1

Cost:  5500 + 4b

Revenue 15b

 

We want to know how many books to sell to break even:

 

15b = 5500 + 4b

11b = 5500

b =5500/11

b = 500 books

 

Cost for 500 books: 5500 + 4(500) = $7500

Revenue for 500 books:  15(500) = $7500