1. **State the problem:** We need to calculate $3 \div \frac{1}{5}$ and express the answer in its simplest form. 2. **Recall the rule for division by a fraction:** Dividing by a fraction is the same as multiplying by its reciprocal. That is, $$a \div \frac{b}{c} = a \times \frac{c}{b}$$ 3. **Apply the rule:** $$3 \div \frac{1}{5} = 3 \times \frac{5}{1}$$ 4. **Multiply:** $$3 \times 5 = 15$$ 5. **Simplify:** The result is already in simplest form. **Final answer:** $$15$$