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5. Jackson purchased a pack of game cards that was on sale for 22% off. The sales tax in his county is 6%. Let y represent the original price of the cards. Write an expression that can be used to determine the final cost of the cards.

1 Answer

5 votes

Answer: 0.8268y

The decimal value is exact without any rounding.

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Step-by-step explanation:

If Jackson saves 22%, then he pays the remaining 100% - 22% = 78%, which leads to the decimal value 0.78

An increase of 6% leads to 100%+6% = 106% and that converts to 1.06

Multiply those decimal values: 0.78*1.06 = 0.8268; this trick is useful to chain together multiple discounts and/or tax increases.

Therefore, the final cost expression is 0.8268y where the variable y is the original price before the discount and taxes.

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Extra info:

The expression 0.8268y tells us that Jackson is paying 82.68% of the original price. Note how 100% - 82.68% = 17.32%

This means Jackson is getting a real discount of 17.32% after the taxes have been considered.

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