1. **State the problem:** Convert 20 miles per hour (mi/hr) to inches per second (in/s). 2. **Recall the conversion factors:** - 1 mile = 5280 feet - 1 foot = 12 inches - 1 hour = 3600 seconds 3. **Set up the conversion:** $$20 \frac{mi}{hr} \times \frac{5280 \ ft}{1 \ mi} \times \frac{12 \ in}{1 \ ft} \times \frac{1 \ hr}{3600 \ s}$$ 4. **Calculate step-by-step:** $$20 \times 5280 \times 12 \times \frac{1}{3600} = \frac{20 \times 5280 \times 12}{3600}$$ 5. **Simplify the fraction:** $$\frac{20 \times 5280 \times 12}{3600} = \frac{\cancel{20} \times 5280 \times 12}{\cancel{3600}} = \frac{20 \times 5280 \times 12}{3600}$$ Note: Actually, cancel 20 and 3600 by dividing numerator and denominator by 20: $$\frac{\cancel{20} \times 5280 \times 12}{\cancel{3600}} = \frac{1 \times 5280 \times 12}{180}$$ 6. **Continue simplifying:** $$\frac{5280 \times 12}{180} = \frac{\cancel{5280} \times 12}{\cancel{180}}$$ Divide numerator and denominator by 60: $$\frac{88 \times 12}{3} = \frac{1056}{3}$$ 7. **Final division:** $$\frac{1056}{3} = 352$$ 8. **Answer:** $$20 \frac{mi}{hr} = 352 \frac{in}{s}$$ This means 20 miles per hour is equivalent to 352 inches per second.