AMC8 2001

AMC8 2001 · Q4

AMC8 2001 · Q4. It mainly tests Parity (odd/even), Digit properties (sum of digits, divisibility tests).

The digits 1, 2, 3, 4 and 9 are each used once to form the smallest possible even five-digit number. The digit in the tens place is

数字1、2、3、4和9各用一次，形成可能的最小的偶五位数。十分位上的数字是

(A) 1 1

(B) 2 2

(D) 4 4

(E) 9 9

Answer

Correct choice: (E)

正确答案：（E）

Solution

To make the number as small as possible, the smaller digits are placed in the higher-value positions. To make the number even, the larger even digit 4 must be the units digit. The smallest possible even number is 12394 and 9 is in the tens place.

为了使数字尽可能小，将较小的数字放在高位。为了使数字为偶，较大的偶数字4必须是个位数字。可能的最小偶数是12394，十分位是9。

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