Question

Serial numbers for a product are to be made using 3 letters followed by 3 numbers. If the letters are to be taken from the first 5 letters of the alphabet with no repeats and the numbers are taken from the digits
0 through 9 with repeats possible, how many serial numbers can be generated?

Answer 1

The first letter has 5 choices, second letter then has 4 choices, the third then has 3 choices.  The first number has 10 choices, second number has 10 choices, third number has 10 choices. 

So to find the total possibilities take 5*4*3*10*10*10 = 60,000