AMC 8 2005 Problem 11
AMC8 2005 年第 11 题
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The sales tax rate in Rubenenkoville is 6%. During a sale at the Bergville Coat Closet, the price of a coat is discounted 20% from its $90.00 price. Two clerks, Jack and Jill, calculate the bill independently. Jack rings up $90.00 and adds 6% sales tax, then subtracts 20% from this total. Jill rings up $90.00, subtracts 20% of the price, then adds 6% of the discounted price for sales tax. What is Jack's total minus Jill's total?
Bergville 地区的销售税税率为 6％。在 Bergville 大衣柜的一次销售中，一件大衣的价格从原价 90 美元起打了 20％的折扣。Jack 和 Jill 两名职员独立计算账单。Jack 先将 90 美元加上 6％的销售税，然后从总额中减去 20％。Jill 先将 90.00 美元减去 20％，然后再在折扣价格的基础上加上 6％的销售税。则 Jack 所得到的价格减去 Jill 所得到的价格的结果是多少？
- A.- $1.06
- B.- $0.53
- C.$0
- D.$0.53
- E.$1.06
正确答案 · Correct Answer
C
解析 · Solution
Solution 1
The price Jack rings up is . The price Jill rings up is . By the commutative property of multiplication, these quantities are the same, and the difference is $0. Reminder: Commutative states abc = bac= acb =..... and is the same in any order. This only works for addition and multiplication.
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