If $p=3n$ and $n=6$, what's the value of $p$? Is it $18$? I'm not to sure, that's why I have asked. I'm thinking if a number precedes a letter then you times it, is this correct?

$p=3n$ and it is given $n=6$.
So,by the method of substitution of $n$ for $6$ we have $p=3\times6=18.$
So,you are correct!!
