Borders vs. Amazon, notes on rounding

To get results to nearest penny, you need to consider how rounding is done.

In Borders, they calculate the discount, round it, then subtract from original price. Then they figure tax on the discounted price (original minus discount) and round that, then add.

This procedure may make a difference of one penny compared to other procedures.

Hint: Borders is the best deal. It isn't even close.

Amazon vs. Borders

There is a new book called: Math Doesn't Suck; how to survive middle school math.

I have two choices; I can buy it at Borders in Saint Paul for the list price of $23.95 and use a 30% off discount coupon. If I do that, I will have to pay 7% sales tax .

Alternatively, I can buy it on line from Amazon.com for $14.37 but will have to pay $3.99 shipping but no sales tax.

Which is the best deal and how much do I save by taking it?

In Minnesota, the discount is applied first and the tax is computed on the discounted price.

Luxury taxes

In Minneapolis, some luxuries are taxed at a high percentage. For example, on some items the tax is 8 1/8% ("8 and one eighth percent"). What is the total price of a $16 item when tax is added?

Hint: convert 1/8 to a decimal. Add to 8. Then proceed as usual.

Senior discount

I was at the Lakewinds co-op on the 11th of September 2007. My food bill was $13.50. There was no tax. I was offered a 5% senior discount. What was my bill, after the discount?

Note: the discount is calculated, then rounded.

Shopping at the Seward Co-op

On September 9 2007 I bought a sandwich at the Seward Co-op for $4.99 and a can of soup for $3.39. In Minneapolis, sandwiches are taxed at 7.15% and canned soup is not taxed.

What was my total bill? How much change did I get from a $10 bill.

Shopping in St. Paul MN

On September 10, 2007 I bought a pencil sharpener for $1.29 and a calculator for $1. Sales tax in St. Paul is 7% rounded to the nearest cent. What was my total cost? I gave the clerk a ten dollar bill, a quarter and two dimes. How much change did I get?

Shopping in Vail, Colorado

Back on June 30, 2007 I bought an egg poacher in Vail, Colorado.

The price was $17.99. Tax in Vail is 4.422%, tax is rounded to the nearest cent. There was an additional tax of 9 cents; this is a surcharge added to maintain shopping centers.

What was my total bill?