Textbooks are exempted from PST in Ontario. If the total cost of a book

including 5% GST is $89, how much GST is paid for the textbook?

4.24

Step-by-step explanation:

Total price = price of the book + 5% of the price of the book

T = total price P = price of the book G = GST

T = P + G

and

G = 5% of P = 0.05P

therefore

T = P + 5%P = 1P + 0,05P = 1.05P

P = T/1.05 = 89/1.05 ≅ 84.76 (it is 84.7619047619)

G = 89 - 84.76 = 4.24