Problema Solution
How many four-digit even numbers can be formed from the digits 0,2,3,5,6, 9 if all four digits are different?
Answer provided by our tutors
First we will count the four-digit even numbers that end on 0:
V(5, 3) = 5!/(5 - 3)! = 5!/2! = 3*4*5 = 60
The number of four-digit even numbers that end on 2 is:
4*4*3 = 16*3 = 48 (since the first number can not be 0)
The number of four-digit even numbers that end on 6 is:
4*4*3 = 16*3 = 48 (since the first number can not be 0)
The total number of four-digit even number is:
60 + 2*48 = 156.