Question

Louisa wants to buy an online movie subscription that is on sale for

15% off. She writes the expression - 0.15c to represent the cost of
the subscription. Rewrite this expression in a different form to show
what percent of the original price she will pay for the online movie
subscription. Then compare your expression with Louisa's. How are
the expressions related? What does each expression tell you about
the problem situation?

Answer 1

• 0.85c
• one is the cost; the other is the discount

Explanation:

a) As a fraction of the original price Louisa will pay ...

0.85c . . . . 85% of the subscription price

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b) Louisa's expression (-0.15c) tells the amount of the discount, not the cost of the subscription. If Louisa were to write the cost of the subscription, her expression would be ...

c - 0.15c

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c) The expression of (a) is the cost of the subscription; the expression Louisa wrote is the amount of cost reduction due to the discount.