8.1.19 Online Shopping

Activity symbolActivity: Online Shopping

A website that you sometimes shop on offers free shipping and no sales tax. This week, they are also having a promotion which will make your entire order 20% off.

You place an order for items that without the discount would cost $45.50. How much will you pay?

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Comment

How much is the 20% discount on the $45.50 order? You can use it to determine the final cost.

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Answer

How about figuring out the discount mentally?

10% of $45.50 is $4.55. Double that to 20%, which is equation left hand side two multiplication dollar times 4.55 equals right hand side dollar times 9.10.

You could also calculate the discount directly, maybe with a calculator: 20% of $45.50 is equation left hand side 0.2 multiplication dollar times 45.50 equals right hand side dollar times 9.10.

The items will cost dollar 45.50 postfix minus dollar 9.10 equals dollar 36.40.

Alternatively: 100 percent negative 20 percent equals 80 percent. You pay 80% of the original price, which is equation left hand side 0.80 multiplication dollar times 45.50 equals right hand side dollar times 36.40.

8.1.18 Leaving a Tip

8.1.20 Going Down, Going Up