Question

若一名工人的工资降低 $20$ %，那么要恰好恢复到原工资，他需要获得多大幅度的加薪？

If a worker receives a $20$ percent cut in wages, he may regain his original pay exactly by obtaining a raise of:

$20$ %

$20$ percent

$25$ %

$25$ percent

$22\dfrac12$ %

$22\dfrac12$ percent

$\$20$

$\$25$

答案：B

知识点：percentage change reverse percentage

难度评级：920

小提示：

降薪后，工资是原来的 $80\%$

After the cut, the wage is $80\%$ of the original

大提示：

求原工资少掉的 $20\%$ 占降薪后工资的百分比

Find the percent of the reduced wage represented by the missing $20\%$ of the original

解答：

若原工资为 $W$ ，则降薪后的工资为 $0.8W$ 。所需增加额为 $0.2W$ ，它占降薪后工资的比例为 $\frac{0.2W}{0.8W}=\frac14=25\%\text{。}$

因此，正确答案是 B。

If the original wage is $W,$ the reduced wage is $0.8W.$ The needed increase is $0.2W,$ which as a fraction of the reduced wage is $\frac{0.2W}{0.8W}=\frac14=25\%.$

Thus, the correct answer is B.

1955 AMC 12 第 7 题

答案：B

难度评级：920

小提示：

大提示：

解答：

其他年份的第 7 题