I put $100 in a savings account. At the end of each year, I earned 10% interest on the balance of my account at that point. With no deposits or withdrawals, after 5 years I had ? (Round to the nearest dollar.)

A) $162      B) $161     C) $160    D) $150

参考答案：B

解析：每年利息为10%，因此，每年年底总额为上一年的1.1倍。100×1.15=161。Round to the nearest dollar 四舍五入到美元

 

Mr. Rice had breakfast one day at a restaurant with Mr. Wheat. When it came time to pay the bill, it was found that Mr. Rice had as many as one-dollar bills as Mr. Wheat had quarters. (Mr. Rice had one-dollar bills only and Mr. Wheat had quarters only.) Rather than each man paying separately, Mr. Rice paid his share of the bill $ 6 to Mr. Wheat. At that point, Mr. Wheat had four times as much money as Mr. Rice. How much money did Mr. Rice have at the beginning?

A) $6    B) $8    C) $9   D) $12  

参考答案：B

解析：Rice只有面值为一美元的纸币，Wheat只有面值为25美分的纸币，两人拥有纸币的张数一样，Rice将6美元给Wheat后，Wheat手里的钱数是Rice的4倍，求Rice手里最初有多少钱？本着求啥设啥的选择，设Rice最初有x美元，因为他只有面值一美元的纸币，因此纸币张数为x，则Wheat最初手里有0.25x美元，列方程，4×（x-6）=6+0.25x，解方程，x=8

 

Lex buys 6 same-priced books and pays with a $50 bill. The change Lex receives is twice the price of a book. Each book costs

 A) $6.25     B) $7.14     C) $8.33    D) $12.50

参考答案：A

【解析】50（6+2）=6.25 答案为A

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