Question

You buy books for 64 cents each, you plan to sell them for 75 cents each. You're left with 100 unsold books, and you lost $12. How many books did you sell ?

Answer 1

The number of books sold is 473.

Step-by-step explanation:

• The original cost of each book = $0.64
• The selling price of each book = $0.75

The difference between the original price and selling price of the book gives the profit per book.

The profit of one book = Selling price - Original price

Let,

• The total number of books be 'x'.
• The number of books sold be 'y'.
• The unsold books is 100.
• The total profit is -12 because it was gone to a loss of $12.

Therefore, the equation is formed as

total Profit = 0.75y - 0.64x

⇒ 0.75y - 0.64x = -12 --------(1)

Total books = sold books + unsold books

x = y + 100

⇒ x-y = 100  -------(2)

Substitute x= 100+y in the eq(1),

0.75y - 0.64(100+y) = -12

0.75y - 64 -0.64y = -12

0.11y = -12 +64

y = 52 / 0.11

y = 472.7

y ≅ 473

The number of book sold is 473 books.

The total number of books is (100+473) = 573 books.