Question

一名职员清点零用现金时，数得 $q$ 枚二十五美分硬币、 $d$ 枚十美分硬币、 $n$ 枚五美分硬币和 $c$ 枚一美分硬币。后来他发现，有 $x$ 枚五美分硬币被当作二十五美分硬币，又有 $x$ 枚十美分硬币被当作一美分硬币。要更正所得总额，他必须：

In checking the petty cash a clerk counts $q$ quarters, $d$ dimes, $n$ nickels, and $c$ cents. Later he discovers that $x$ of the nickels were counted as quarters and $x$ of the dimes were counted as cents. To correct the total obtained the clerk must:

不作更正

make no correction

减去 $11$ ¢

subtract $11$ ¢

减去 $11x$ ¢

subtract $11x$ ¢

加上 $11x$ ¢

add $11x$ ¢

加上 $x$ ¢

add $x$ ¢

答案：C

知识点：coin values accounting error linear expression

难度评级：1280

小提示：

每把一枚五美分硬币当作二十五美分硬币，总额就会多算 $20$ ¢

Each nickel counted as a quarter makes the total too large by $20$ ¢

大提示：

每把一枚十美分硬币当作一美分硬币，总额就会少算 $9$ ¢

Each dime counted as a cent makes the total too small by $9$ ¢

解答：

把 $x$ 枚五美分硬币当作二十五美分硬币，使总额多算 $20x$ ¢。把 $x$ 枚十美分硬币当作一美分硬币，使总额少算 $9x$ ¢。因此净多算了 $20x-9x=11x$ 美分，必须减去这个数额。

因此，正确答案是 C。

The $x$ nickels counted as quarters overstate the total by $20x$ ¢. The $x$ dimes counted as cents understate it by $9x$ ¢. The net overstatement is $20x-9x=11x$ cents, so that amount must be subtracted.

Thus, the correct answer is C.

1955 AMC 12 第 23 题

答案：C

难度评级：1280

小提示：

大提示：

解答：

其他年份的第 23 题