The number of books sold is 473.
Step-by-step explanation:
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,
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.
