I got a variant in an online interview: You have nine balls, one of which is heavier. How many weightings does it take to find the heavy one. I wrote back, "

I got a variant in an online interview: You have nine balls, one of which is heavier. How many weightings does it take to find the heavy one. I wrote back, "What is the maximum number of balls among which you can find he heavy one in four weightings? If you know the answer to that,then you know I know the answer to your problem." I didn't hear back. I guess HR didnt have a sense of humor.