A store bought an airplane poster and marked it up 100% from the original cost of $5. Later on, Isabella purchased the airplane poster
and paid 10% sales tax. How much, including tax, did she pay for the
airplane poster?

Which of the following statements is true? a. the irrational number system is not closed under multiplication, because the product of two irrational numbers is always a rational number. b. the irrational number system is not closed under multiplication, because the product of two irrational numbers is not always an irrational number. c. the irrational number system is closed under multiplication, because the product of two irrational numbers is always an irrational number. d. the irrational number system is closed under multiplication, because the product of two irrational numbers is always a rational numbers. reset submit