1. **State the problem:** Elsie, Ruby, and Alfred drove a total of 320 miles. Elsie drove $\frac{1}{4}$ of the distance, Ruby drove $\frac{5}{8}$ of the distance, and we need to find how many miles Alfred drove. 2. **Write down the known parts:** - Total distance: 320 miles - Elsie's distance: $\frac{1}{4} \times 320$ - Ruby's distance: $\frac{5}{8} \times 320$ 3. **Calculate Elsie's distance:** $$\frac{1}{4} \times 320 = \frac{320}{4} = 80$$ miles 4. **Calculate Ruby's distance:** $$\frac{5}{8} \times 320 = 5 \times \frac{320}{8} = 5 \times 40 = 200$$ miles 5. **Calculate Alfred's distance:** Alfred drove the remaining distance after Elsie and Ruby. $$\text{Alfred's distance} = 320 - (80 + 200) = 320 - 280 = 40$$ miles 6. **Answer:** Alfred drove $40$ miles.