How many whole numbers between $$1$$ and $$100$$ are $$3$$ times a prime? 
Overseas Competition->Knowledge Point->Number Theory Modules->Prime and Composite Numbers->Determining Prime and Composite Numbers
The prime is $${}\textless33$$, so it could be $$2$$, $$3$$, $$5$$, $$7$$, $$11$$, $$13$$, $$17$$, $$19$$, $$23$$, $$29$$, or $$31$$. 