How many three-digit numbers can be formed under the following condition?
The leading digit cannot be zero and the number must be even.

A)900
B)450
C)350
D)400
E)550

Question

How many three-digit numbers can be formed under the following condition? ​
The leading digit cannot be zero and the number must be even.
​
A)900
B)450
C)350
D)400
E)550

Quizplus · Accepted Answer

The first digit can be chosen in 4 ways (2,4,6,8). The second digit can be chosen in 10 ways (0,1,2,...,9) and the third digit can also be chosen in 10 ways.
Therefore, the total number of three-digit numbers that can be formed is 4×10×10=400. However, we have to exclude the numbers that start with 0. The number of such numbers is simply 10 (0 cannot be the leading digit). Subtracting these, we get 400−10=390.

How Many Three-Digit Numbers Can Be Formed Under the Following