Question

How many four digit numbers can be formed from the numbers 1,3,4,6,8 and if repetition of number is not allowed?

Answer 1

a lot...

Total even numbers: 4⋅6⋅5⋅4=4804⋅6⋅5⋅4=480

Total 3-digit even numbers: 3⋅5⋅4⋅1=603⋅5⋅4⋅1=60

Total 4-digit even numbers: 480−60=420