Amos counts out loud by six beginning with $0.$ Sarah counts out loud by three also beginning with $0.$ Between $0$ and $100$ inclusive, how many of the numbers do both Sarah and Amos say out loud?
Well, notice that LCM[6, 3], is 6, so every factor of 6 between 0 and 100 is a factor.
We have \(100/6=16.67\), rounding down means there are 16 factors.
However, this is not including 0, so we add 1 to get 17.
So both Sarah and Amos say 17 numbers out loud.
Thanks! :)