Final answer:
To travel 800 miles in 16 hours, a car must travel at a speed of 50 mph. The calculation is based on the formula for speed, which is distance divided by time.
Step-by-step explanation:
To find out how fast in miles per hour a car must travel to go 800 miles in 16 hours, we need to use the formula for speed: speed = distance/time. So, we divide 800 miles by 16 hours to get the car's speed.
800 miles ÷ 16 hours = 50 miles per hour (mph)
Therefore, to travel 800 miles in 16 hours, a car must travel at 50 mph. The correct answer is B) 50 mph.