Problema Solution
Suppose you write a book. The printer charges $4 per book to print it, and you spend $3500 on advertising. You sell the book for $15 a copy. How many copies must you sell so that your income from sales is greater than your total cost?
Answer provided by our tutors
If the number of books sold = x
then total cost to be less than the sales income => 4x+3500 < 15x;
11x > 3500;
Or, x > 318.2
So, he must sell more than 318 books for his income to be more than expenditure.