smc

If Charles has $5q+1$ quarters and Richard has $q+5$ quarters, then the difference between them is $4q-4$ quarters. Converting quarters to dimes, the difference between them is $\frac{5}{2}\cdot (4)(q-1)$, or $10(q-1)$ dimes, $⟹\boxed{10(q-1)}$ Note that $q$ does not stand for the number of quarters that they have.