- Thread starter
- #1

I am told the answer is 1200.

I do not believe that I am able to use the standard combination formula.

This is what I did which I got the correct answer but do not really believe I am able to do this every time.

The first Number I can chose from 30.

The Second #, Chose from 20.

The 3rd #, Chose from 12.

So 30*20*12= 7200

7200/6= 1200

I divided by 6 since I am choosing 3 numbers and I multiplied that by 2 since I have to get rid of each row and column when a number is chosen.

Will this always work? Does an easier way exist?