“You cannot ride the roller coaster if you are under 4 feet tall unless you are older than 16 years old.”
Let $p,q,r$ be the following propositions :
$p:$ “You can ride the roller coaster.”
$q:$ “You are under 4 feet tall.”
$r:$ “ You are older than 16 years old.”
Now, Let's Express the sentence in terms of propositions $p, q,$ and $r$ :
$(q ∧ ¬r) → ¬p$