examday

/TMUA

Consider the following claim about positive integers $a$, $b$ and $c$:

if $a$ is a factor of $bc$, then $a$ is a factor of $b$ or $a$ is a factor of $c$

Which of the following provide(s) a counterexample to this claim?

• I. $a=5$, $b=10$, $c=20$
• II. $a=8$, $b=4$, $c=4$
• III. $a=6$, $b=7$, $c=12$