Question

如图所示，一个 $4 \times 4$ 的日历日期方块。先将第二行数字的顺序反过来。然后将第四行数字的顺序反过来。最后，把两条对角线上的数字分别相加。两个对角线和的正差是多少？

A $4 \times 4$ block of calendar dates is shown. The order of the numbers in the second row is to be reversed. Then the order of the numbers in the fourth row is to be reversed. Finally, the numbers on each diagonal are to be added. What will be the positive difference between the two diagonal sums?

$2$

$4$

$6$

$8$

$10$

答案：B

知识点：日期与时间过程模拟

难度评级：880

解答：

将第二行反为 $11,10,9,8$ ，第四行反为 $25,24,23,22$ 后，两条对角线分别为 $1,10,17,22$ 和 $4,9,16,25$ 。

它们的和为 $1+10+17+22=50$ 和 $4+9+16+25=54$ ，正差为 $54-50=4$ 。

所以正确答案是 B。

After reversing the second row to $11,10,9,8$ and the fourth row to $25,24,23,22,$ the two diagonals are $1,10,17,22$ and $4,9,16,25.$

Their sums are $1+10+17+22=50$ and $4+9+16+25=54,$ so the positive difference is $54-50=4.$

Thus, the correct answer is B.

2008 AMC 10B 第 2 题

答案：B

难度评级：880

解答：

其他年份的第 2 题