jmc

To get from 6 to 72 we multiply by 12, so a fraction equivalent to $\frac{5}{6}$ whose denominator is 72 has a numerator of $n=5\cdot 12=60$. We can solve $\frac{5}{6}=\frac{60+m}{84}$ similarly to obtain $m=10$. Finally, $\frac{5}{6}=\frac{p-10}{120}⟹p-10=100⟹p=\boxed{110}$.