Question, If repetition is not permitted, how many even three-digit numbers can be formed...

Question

1.If repetition is not permitted, how many

even three-digit numbers can be formed

from the digits

a)1, 2, 3, 4, 5, 6? <- is it 2.4.6?

b)0, 1, 2, 3, 4, 5?<- 2.4

Please explain, I am so confused.

Answer 1

To be even the number must end in either 2, 4, or 6

For a number ending is 2, there are 5 numbers for the first place and 4 for the second, for a total of 20.

This is the same for a number ending in 4, and 6.

Therefore a total of 60 different numbers.

For the second set the number must end in 0, 2, or 4.

Using the reasoning above can you determine the number of numbers?